TALC NOT CONTAINING ASBESTIFORM FIBRES 1. Exposure Data

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					         TALC NOT CONTAINING ASBESTIFORM FIBRES


                                   1. Exposure Data

Introduction
    Talc refers to both mineral talc and industrial mineral products that are marketed
under the name talc and contain proportions of mineral talc that range from about 35% to
almost 100%.
    The mineralogy of airborne particles in talc mines is restricted by that of the deposit
and associated rocks. Therefore, mines and mills provide an opportunity to characterize
exposure to one specific source of talc mineralogically. In contrast, the mineralogy of talc
in an industrial setting where talc products are used may be difficult to characterize,
because many different sources of talc are available for almost every application.
Industrial talcs are quite variable in their talc content and in the identity and proportion of
other minerals that they contain. In addition, talc is part of a complex mixture of materials
in user industries.
    Talc particles are normally plate-like. When viewed under the microscope in bulk
samples or on air filters, they may appear to be fibres and have been identified as such.
Talc may also form as true mineral fibres that are asbestiform; asbestiform describes the
pattern of growth of a mineral that is referred to as a ‘habit’. Asbestiform talc fibres are
very long and thin and occur in parallel bundles that are easily separated from each other
by hand pressure.
    Asbestos is a commercial term that describes six minerals that occur in the
asbestiform habit: actinolite, anthophyllite, chrysotile, grunerite, riebeckite and tremolite
(IARC, 1977). Similarly to talc, these six minerals occur more commonly in a non-
asbestiform habit, and may also be elongated without being asbestiform. Actinolite,
anthophyllite and tremolite may occur in some talc deposits; when asbestiform, they
constitute asbestos and, when not asbestiform, they are referred to as mineral fragments or
cleavage fragments.




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278                         IARC MONOGRAPHS VOLUME 93

1.1      Chemical and physical data

1.1.1    Nomenclature
    CAS Registry No.: 14807–96–6
    Chem. Abstr. Name: Talc
    Synonyms1: Soapstone; steatite; talcum
    Trade names1: Trade names of industrial, cosmetic and pharmaceutical talc include
    Agalite, Asbestine, Australian microcrystalline, Beaver White 200, CP 10–40,
    CP 38–33, Crystalite CR 6002, Desertalc 57, Emtal 500, Emtal 549, Emtal 596,
    Emtal 599, Ex-IT, Fibrene C 400, Finntalc, French Chalk, FW-XO, HSDB 830, IT
    Extra, LMR 100, Microneeca K1, Micro White 5000A, Microtalco IT Extra, Mistron,
    Montana talc, MP 25–38, MP 40–27, MP 45–26, MST, MT 12–50, Mussolinite,
    NCI-CO6018, Nytal 200, Nytal 400, Pk-C, Pk-N, Plustalc, Polytal 4641, Polytal
    4725, Snowgoose, Steawhite, Supreme, Supreme dense, Talcan PK-P, Talcron
    CP 44–31 and Westmin.
    Rocks or mineral composites that contain talc mineral include agalite, potstone,
soapstone and talcite. Soapstone generally contains at least 25% of minerals other than
talc while talcite is sometimes used to describe rock that contains at least 75% talc
(Harben & Kuzvart, 1996). Steatite originally referred to a rock that is relatively pure talc;
today, it denotes a ceramic body with a high talc content that is used as an electrical
insulator. The talc that is used in such applications is known as steatitic talc. French chalk
is soft massive talc (Piniazkiewicz et al., 1994). Talc has also been referred to as
snowgoose, agalite and kerolite. Industrial talc generally refers to products that contain
abundant minerals other than talc; cosmetic talc now normally contains >98% talc
(Zazenski et al., 1995) but the content may have been lower in the past (Rohl et al.,
1976). Pharmaceutical talc contains >99% talc. Talcum powder is cosmetic-grade talc
(Zazenski et al., 1995). Pyrophyllite is similar to talc in atomic structure but contains
aluminium instead of magnesium (Al2Si4O10(OH)2) (Bish & Guthrie, 1993); the two
minerals do not occur together in nature, although they have similar industrial
applications.

1.1.2    Structure of the typical mineral
    Chemical formula: Mg3Si4O10(OH)2
    Molecular weight: 379.26
    The original X-ray spectra of talc (Gruner, 1934; Hendricks, 1938) indicated that
mineral talc had a monoclinic structure. Later investigations (Ross et al., 1968; Rayner &
Brown, 1973) demonstrated that talc is triclinic (Table 1.1). The small deviations from
90° in angle α and angle γ result in the triclinic symmetry. Indexing the X-ray diffraction

1
 These synonyms and trade names cover talc, materials that contain talc and talc that is
contaminated with other minerals as admixtures.
                                            TALC                                              279

pattern as a monoclinic structure assumes that angles α and γ are each 90° and doubles the
magnitude of one of the lattice parameters (parameter ‘c’ in Table 1.1).

    Table 1.1. Lattice parameters and crystallographic axes of talc

    Lattice parameters (nm)    Crystallographic axes      System      References
    a        b        c        α        β        γ

    0.5255   0.9137   0.9448   90°46′   98°55′   90°00′   Triclinic   Ross et al. (1968)
    0.5293   0.9179   0.9496   90°57′   98°91′   90°03′   Triclinic   Rayner & Brown (1973)


    The structure of talc is characterized by a hexagonal sheet arrangement of silicon–
oxygen tetrahedral groups linked in a common plane. Each silicon–oxygen tetrahedron
shares three planar oxygen atoms with its neighbouring tetrahedra; the fourth oxygen, the
apex of the tetrahedron, is not shared. Two such sheets are orientated so that unshared
apical oxygen atoms face each other. The sheets are bonded by magnesium atoms that are
coordinated octahedrally by two oxygen atoms from each tetrahedral sheet and two
hydroxyl groups. This structural arrangement results in a double-sheet structure in which
the valence demands of the constituent atoms are completely satisfied without interlayer
cations; these double-sheet units are held together only by weak van der Waal’s bonds.
The double-sheet units are easily separated by slight forces that result in a perfect
cleavage direction in the basal plane (Rohl et al., 1976; Pooley & Rowlands, 1975). The
structure of talc is depicted in Figure 1.1 (see cover photo of this Volume).

1.1.3    Chemical and physical properties of mineral talc
    Hardness: 1 on Mohs’ scale
    Density: 2.58–2.83
    Cleavage: (001) perfect
    Colour: Pale to dark green or greenish grey to black; also white, silvery-white, grey,
    brownish
    Luster: Translucent; pearly, greasy or dull
    Indices of refraction: Talc is biaxial with α=1.539–1.550, β=1.589–1.594 and
    γ=1.589–1.600. The indices of refraction increase with iron content. Because β and γ
    are approximately equal, talc appears to be uniaxial (Deer et al., 1962).
    Description: Commonly thin tabular crystals, up to 1 μm in width; talc is usually
    massive, fine-grained and compact; it also occurs as foliated or fibrous masses or in
    globular stellate groups. Talc particles are normally thin and plate-like, but the size of
    the individual plates varies among different bodies of ore. When viewed under the
    microscope on end, talc platelets may appear as fibres (Cralley et al., 1968). These are
    not true fibres and should not be confused with asbestiform talc. Asbestiform talc is
                                                              280
Figure 1.1 Schematic structure of talc




                                                              IARC MONOGRAPHS VOLUME 93
From NIMSoffice, http://en.wikipedia.org/wiki/File:Talc.GIF
                                          TALC                                          281

    formed when talc plates elongate parallel to the a axis within the plate to form true
    ribbon-like fibres of talc. These fibres may occur in an asbestiform habit consisting of
    bundles of narrow fibres randomly oriented around the axis of elongation (c axis). In
    some deposits, including those in the Gouverneur District of New York State, a small
    proportion of talc fibres are intergrown on a nanoscale with amphiboles (Stemple &
    Brindley, 1960; Greenwood, 1998; Wylie et al., 1997).
    Chemical composition: The ideal formula is Mg3Si4O10(OH)2. When expressed in the
    standard oxide form, the ideal chemical composition is: 31.9% MgO, 63.4% SiO2 and
    4.8% H2O (Piniazkiewicz et al., 1994). No talc is ideal, and small amounts of
    aluminium and iron are common impurities. Aluminium may substitute for both
    magnesium and silicon; iron(II) and iron(III) may substitute for magnesium. Talc that
    has almost all magnesium substituted by iron is called minnesotaite and is abundant in
    the iron formations of Minnesota, USA (Deer et al., 1962). Fluorine is the most
    common substitution for the hydroxy group (Petit, 2005). Small amounts of nickel,
    chromium, calcium, potassium, sodium and manganese are also found in the
    octahedral sites while titanium may substitute for silicon in the tetrahedral site.
    Table 1.2 provides examples of the variability in the composition of mineral talcs, talc
    ores and talc products.
    Solubility: The solubility of talc has been described in detail by Jurinski and Rimstidt
    (2001). On the sole basis of dissolution under pulmonary conditions, authors
    estimated that the maximum residence time in the lung of a 1-μm ‘spherical’ particle
    of talc is approximately 8 years. The reader is referred to Section 4 for a detailed
    description of the kinetics of deposition and clearance.

1.1.4    Chemical and mineralogical characteristics of talc deposits
    Talc ore deposits are formed from the hydrothermal metasomatism of pre-existing
rocks by fluids that contain silicon and/or magnesium. Hydrothermal fluids may be
derived from fluids that migrate during retrograde or prograde regional metamorphism or
from contact metamorphism that is associated with nearby or distant intrusive igneous
rocks. The chemical composition of talc and its associated minerals result from the
original rock type, the nature of the hydrothermal alteration and metamorphic history
(Harben & Kuzvart, 1996).
    The chemical and mineral compositions of talc from various locations are shown in
Tables 1.2 and 1.3, respectively.

         (a)    Talc derived from mafic and ultramafic rocks
    Talc deposits, the protoliths of which are ultramafic (or mafic) rocks, are abundant in
number but small in total production. They are found in discontinuous bodies in orogenic
belts, such as the Alps, the Appalachians and the Himalayas, and form during the regional
metamorphism that accompanies orogenesis. They also occur in Canada (Ontario and
Quebec), Egypt, Finland, Germany, Norway, the Russian Federation (Shabry and Miassy),
                                                                                                                                                                             282
Table 1.2 Chemical composition (wt%) of selected mineral talcs, talc ores and talc mineral products

Component Mineral talca,b                                                               Talc oresc

             1       2       3       4       5       6        7       8        9        1d       2d      3d       4d     5e       6e      7e       8e       9f      10g

SiO2         62.61   62.67   62.47   62.16   60.06   60.02    60.88   61.07    51.29    70.8     49.8    44.6     44.8   35.98    59.15   62.65    59.80    54.92   60
TiO2         –       –       –       –       –       –        0.10    –        0.04     0.07     0.03    0.03     0.06   0.02     –       –        –
Al2O3        –       0.38    0.47    0.88    1.60    1.88     1.98    2.42     0.61     0.69     0.48    0.45     1.20   0.43     0.26    0.31     0.57             0.70
Fe2O3        –       0.68    –       –       –       –        0.83    1.49     2.00     0.86     0.29    0.51     0.46   0.65     3.36    1.51     0.05     0.46    2.2




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FeO          2.46    0.65    0.79    1.41    1.74    1.51     –       –        33.66    –        –       –        –      5.96     –       –        0.15
MnO          0.01    –       0.00    –       –       –        –       –        0.12     0.01     0.02    0.03     0.03   0.41     –       –        0.39
MgO          30.22   29.95   31.76   30.86   30.83   30.39    31.18   29.13    6.26     23.2     19.9    23.2     25.0   32.95    31.34   30.23    27.45    27.20   31
CaO          –       1.35    0.00    –       0.40    1.00     0.14    0.75     0.00     0.07     10.4    14.7     9.98   0.00     0.15    Trace    6.80     5.76
Na2O         –       –       –       –       –       –        –       –        0.08     <0.15    <0.15   <0.15    0.59   0.00     –       0.15     –
K2O          –       –       –       –       –       –        –       –        0.03     <0.02    0.31    <0.02    0.93   0.00     –       0.05     –
Loss on                                                                                 3.99     18.1    16.0     16.1   23.18    6.06    5.14     5.93     10.76   5.80
ignition
NiO                                                                                     –        –       –        –      0.21     –       –        –
Cr2O3                                                                                                                    0.18
H2O+         4.72    5.05    4.70    4.92    5.02    5.37     4.98    4.82     5.54
H2O–         –       –       0.06    –       –       0.32     –       –        0.24

a
  From Deer et al. (1962)
b
  1, Talc, altered periodotite (Muruhatten, northern Sweden); 2, Talc (Shabrov, Urals, USSR); 3, Talc (Murphy, NC, USA); 4, Light-green talc (Malangen, Norway);
5, Green talc, altered serpentine (Parma district, Apennines, Italy); 6, Black talc, with carbonaceous material derived from a bluish gray rock (Parma, Apennines, Italy);
7, Talc (Mount Fitton, South Australia); 8, Talc, altered tremolite (Yellandu Warangal district, Hyderabad, India); 9, Greenish gray iron talc (minnesotaite) (East Mesabi
range, MN, USA)
c
  1, Talc rock (Alliance Mine, CA, USA); 2, Talc ore (Pleasanton Mine, CA, USA); 3, Talc ore (Talc City, USA); 4, Talc ore (Acme Mine, CA, USA); 5, Vermont talc–
magnesite ore (USA); 6, Flotation product (Johnson, VT, USA); 7, Steatite (Yellowstone Mine, MT, <USA); 8, Average ore (Talcville, NY, USA); 9, Texas talc (USA);
10, FINNTALC M30
d
  From Van Gosen et al. (2004)
e
  From Chidester et al. (1964)
f
  From Pence (1955)
g
  From Mondo Minerals (2005)
                                          TALC                                             283

southern Spain and the USA (Arkansas, California and Texas) (Piniazkiewicz et al., 1994;
Harben & Kuzvart, 1996). These deposits may contain trace amounts of nickel, cobalt and
chromium that are derived from their ultramafic protolith. One major talc deposit in
eastern USA contains substantial amounts of nickel (up to 0.2%; Rohl et al., 1976).
Nickel-substituted talc is also associated with serpentine bodies, at up to 0.5% by weight
(Pooley & Rowlands, 1975); pentlandite has been reported in talc from Finland from
which it is recovered by flotation (Harben & Kuzvart, 1996). Quartz is uncommon in talc
that has mafic or ultramafic protoliths and the fluorine content is generally low (Ross
et al., 1968). Chlorite and amphiboles are usually associated with this type of talc deposit
although they are commonly separated in space from the talc ore (Vermont). The
amphiboles may or may not be asbestiform, depending on the local geological history. A
small amount of amphibole asbestos is associated with this type of talc deposit at
Soapstone Ridge, GA (USA) and anthophyllite asbestos is abundant in the vicinity of the
talc at Dadeville, AL (USA) (Van Gosen et al., 2004). In a few deposits, the parent was
mafic rock (Virginia (Schuyler), Georgia and Egypt) (Harben & Kuzvart, 1996).

  Table 1.3. Mineral composition (wt%) of talc from various locations

  Mineral           Montana   Vermont   North Carolina   New Yorka    California   France

  Talc              90–95     80–92     80–92            35–60        85–90        70–90
  Tremolite         –         –         –                30–55        0–12         –
  Anthophylite      –         –         0–5              3–10         –            –
  Serpentine        –         –         –                2–5          –            –
  Quartz            <1        <1        1–3              1–3          <1           <1
  Chlorite          2–4       2–4       5–7              –            –            10–30
  Dolomite          1–3       1–3       2–4              0–2          0–3          –
  Calcite           –         –         –                1–2          –            –
  Magnesite         0–5       0–5       –                1–3          –            –

  From Harben & Kuzvart (1996)
  a
    Gouverneur District


            (b)   Talc derived from magnesium carbonates
     Talc deposits formed from the alteration of carbonate and sandy carbonate such as
dolomite and limestone are the most important in terms of world production. Two types
are recognized: (i) those derived from hydrothermal alteration of unmetamorphosed or
minimally metamorphosed dolomite (Australia (Mount Seabrook and Three Springs),
China, India, Republic of Korea, the Russian Federation (Onot), northern Spain (Respina)
and the USA (Alabama (Winterboro), California (Talc City), Montana (Yellowstone),
Washington (Metaline Falls) and West Texas); and (ii) those derived from hydrothermal
alteration (including retrograde metamorphism) of regionally metamorphosed siliceous
dolomites and other magnesium-rich rocks (Austria (Leogen), Brazil (Brumado), Canada
284                        IARC MONOGRAPHS VOLUME 93

(Madoc), France (Trimouns), Germany (Wunsiedel), Italy (Chisone Valley), the Russian
Federation (Krasnoyarsk), Slovakia (Gemerska Poloma), Spain and the USA
(Chatsworth, GA, Death Valley–Kingston Range, CA, Murphy Marble belt, NC, and
New York). In a few of these deposits, including the large deposit at Trimouns, France,
the talc may be classified as being derived from alumino-silicate rocks (Harben &
Kuzvart, 1996; Luzenac, 2004).
     Talc derived from magnesium carbonate may contain quartz. Van Gosen et al. (2004)
suggested that, among the first group, only those that are formed by hydrothermal
alteration of dolomites that are in direct contact with igneous bodies are probably
accompanied by amphiboles (e.g. Death Valley, CA, USA) and that hydrothermal
deposits in carbonates that are formed by relatively low-temperature fluids derived from
distant igneous bodies contain no or only very minor amounts of amphibole (Talc City,
CA, Southwestern Montana and Allamoore, TX, USA). In some deposits in the second
group, amphiboles may be very abundant, especially those formed during high-
temperature regional metamorphism of impure dolomites. In the Gouverneur District
New York State, for example, non-asbestiform tremolite comprises between 30 and 70%
of the talc product (Harben & Kuzvart, 1996).
     Gouverneur District New York State talc that is currently marketed under the trade
name Nytal is a unique industrial mineral product that can readily be distinguished from
all other commercially available industrial talcs based on its mineral content. Nytal 100,
for example, contains 30–50% tremolite, 20–40% talc, 20–30% serpentine, 2–10%
anthophyllite and 0.14% quartz (R.T. Vanderbilt Company, 2000). The tremolite,
anthophyllite and serpentine occur as mineral fragments and not as asbestiform fibres.
Tremolite from this deposit has been characterized in detail (Campbell et al., 1980). Nytal
also contains asbestiform fibres of talc and talc intergrown on a nanoscale with amphibole
(Wylie et al., 1997). Wylie et al. (1997) estimated that the abundance of particles that are
longer than 5 μm and have an aspect ratio of 3:1 or greater in sample FD14 (identified as
a commercial talc product from New York State) is 0.8×103/μg; 62% of these particles
were identified as talc, 24% as fragments of tremolite plus a small amount of
anthophyllite and 14% as talc intergrown with anthophyllite. Products from other mines
in this district before 1964 contained different proportions of anthophyllite and tremolite,
which may be asbestiform (Chidester et al., 1964).

         (c)    Minerals associated with talc
    Because talc deposits are formed from different protoliths under many different
geological conditions, each talc deposit has a combination of mineralogy and mineral
habit that is distinctive and, in many cases, unique. The most common minerals found in
talc products include chlorite, magnesite, dolomite, tremolite, anthophyllite, serpentine
and quartz. However, many other minerals have been reported; these are given in
Table 1.4 (Pooley & Rowlands, 1975; Piniazkiewicz et al., 1994; Harben & Kuzvart,
1996). Some of these minerals are beneficial to certain applications such as tremolite in
ceramics.
                                                 TALC                                           285

 Table 1.4. Minerals commonly associated with talc

 Mineral group         Name                                      Ideal formula

 Carbonate             Dolomite                                  (Ca,Mg)CO3
                       Magnesite                                 MgCO3
                       Breunnerite                               (Mg,Fe)CO3
                       Calcite                                   CaCO3
                       Siderite                                  FeCO3
                       Ankerite                                  Ca(Fe,Mg,Mn)(CO3)2
 Phyllosilicates       Chlorite                                  (Mg,Al,Fe)12(Si,Al)8O20 (OH)16
                       Serpentine (lizardite and antigorite)     Mg3Si2O5(OH)4
                       Phlogopite (mica)                         K2(Mg,Fe)6Si6Al2O20(OH)4
                       Sepiolite                                 Mg8Si12O30(OH)4(H2O)4
 Amphibolea            Tremolite                                 Ca2Mg5Si8O22(OH)2
                       Anthophyllite                             (Mg,Fe)7 Si8O22(OH)2
                       Actinolite                                Ca2(Mg,Fe)5 Si8O22(OH)2
 Tectosilicates        Quartz                                    SiO2
                       Feldspar                                  (K,Na)AlSi3O8
 Oxides                Magnetite                                 Fe3O4
                       Ilmenite                                  FeTi O3
                       Manganese oxide                           MnO2
                       Rutile                                    Ti O2
 Sufides               Pyrite                                    FeS2
                       Pyrrhotite                                FeS
                       Pentlandite                               (Fe,Ni)9S8
 Other minerals        Tourmalineb                               NaFe3Al6(BO3)3Si6O18(OH)3(OH)
                       Graphite                                  C

 Compiled by the Working Group from Pooley & Rowlands (1975); Piniazkiewicz et al. (1994);
 Harben & Kuzvart (1996)
 a
   See Leake et al. (1997) for precise nomenclature and chemical composition of the amphibole
 group.
 b
   This is the formula for one member of the tourmaline group; chemistry is highly variable.


           (d)     Chemical composition of talc ore
    The variability in the chemical composition of talc ore, talc mineral products and talc
rock primarily reflects their mineral composition (see Table 1.2).
286                        IARC MONOGRAPHS VOLUME 93

1.1.5    Processing of talc ores and composition of talc products
     Talc ores may be processed by a variety of techniques that include selective mining,
hand sorting and milling by roller mills, hammer mills, ball mills, fluid energy mills and
jet mills and are classified and separated from other minerals by froth flotation or
magnetic separation. Some may be treated with acid and calcined. The particle sizes of
talc and the abundance of the associated minerals are determined by characteristics of the
ore, methods of processing, and the duration of grinding. Grinding breaks the talc
platelets along (001) and disaggregates the particles; prolonged grinding may destroy the
crystallinity (Sanchez-Soto et al., 1997; Zbik & Smart, 2005). Roller mills tend to
preserve the platy structure and different types of milling affect properties such as
flatness, surface roughness, roundness, width and elongation (Yekeler et al., 2004). Talc
particles are platy, and sizes reflect the dimension parallel to the plate; data are not
available on the thinness of the plates.
     Talc products also vary in particle size; median sizes range from ~1 to >20 μm and
top sizes range from <10 to >100 μm. The most common designations for fineness are
based on US Sieve Series and Tyler equivalence and include 200 mesh (95–98%
<74 μm), 325 mesh (95–99% <44 μm) and 400 mesh (95–99% <37 μm) (Zazenski et al.,
1995).
     Talc products that contain >95% mineral talc are used in cosmetics, baby powder,
pharmaceuticals, steatite ceramics, pitch control in the paper industry and as a filler in
rubber. Today, the talc in baby powders is >99% 200 mesh (Zazenski et al., 1995). Talc
products that contain between 75 and 95% mineral talc are used in paper fillers,
reinforced plastics, paint, ceramics and dusting compounds for rubber. Lower-purity talc
is used in roofing material, patching compounds, flooring and fertilizers (Piniazkiewicz
et al., 1994). Particle sizes, colour and nature of associated minerals also vary among
these applications.

1.1.6    Analysis
         (a)    Analysis of bulk samples
     Talc can be identified from its optical properties by polarized light microscopy and oil
immersion, from its X-ray or electron diffraction pattern, from its chemical composition
and from differential thermal analysis/thermal gravimetric analysis. Chlorite has similar
optical properties. Talc platelets on end and talc intergrown with amphibole in fibrous talc
have complex electron diffraction patterns that may resemble other silicates, including
amphiboles (Stemple & Brindley, 1960) and sepiolite (Germine, 1987), unless carefully
indexed. Anthophyllite and sepiolite have chemical compositions that are very similar to
talc and require quantitative chemical analysis to differentiate them, including the use of
well characterized standards in the case of dispersive X-ray analysis used in conjunction
with electron microscopy. Identification of mixed mineral assemblages by X-ray
                                           TALC                                          287

diffraction may be difficult because of pattern overlap (Krause, 1977) and X-ray
diffraction cannot distinguish asbestiform minerals from other habits.
     Particle size distributions that are determined by settling underestimate the abundance
of larger particles and overestimate the number of smaller particles because the platy
structure results in longer settling times for talc compared with spherically shaped
particles of equivalent size. Computer-controlled scanning electron microscopy has been
used to provide a more accurate size distribution. Determination of the respirable fraction
of bulk materials by these two methods differs significantly (Zazenski et al., 1995).

         (b)    Analysis of exposure
     The standard methods for the analysis of airborne exposures in an occupational
setting where asbestos is known to be present include those of the Health and Safety
Executive (1995) and the Occupational Safety and Health Administration (2005). These
methods were designed to provide an index of exposure since they count only particles
longer than 5 μm with a length-to-width ratio of 3:1 or more that are visible by phase-
contrast microscopy. They do not determine the mineral identity of the particles counted.
In a mining environment where many minerals form elongated fragments, the results of
fibre counts can be difficult to interpret. In bulk samples of talcum products, for example,
Cralley et al. (1968) reported that particles longer than 5 μm with a 3:1 aspect ratio in
22 talcum products represented 19% of the particles, which were predominantly talc.
     Conversion of fibre counts to gravimetrically based exposure metrics is complicated
as this will depend on the particle size. Oestenstad et al. (2002) adjusted million particles
per cubic foot (mppcf) to milligrams per cubic metre (mg/m3) using the following
regression equation:
                              ln (mg/m3)=ln (mppcf)×0.62–1.20
    All gravimetric measurements to monitor exposure to talc in occupational settings are
taken from samples of respirable dust particles. The reader is referred to the Glossary and
the monograph on carbon black for further details.

1.2      Production and use

1.2.1    Production
    Talc deposits result from the transformation of existing rocks under hydrothermal
activity and are classified according to the parent rock from which they derive. There are
three broad types of talc deposit of commercial significance (Luzenac, 2004;
EUROTALC, 2005; Industrial Minerals Association-Europe, 2005): (i) talc derived from
mafic and ultramafic rocks, which provides about 40% of talc supplies; the crude ore is
usually grey and, to be commercially viable, may be upgraded to improve the mineralogy
and whiteness (generally by flotation); (ii) talc derived from magnesium carbonates,
which provides >50% of world production; and (iii) talc derived from alumino-silicate
288                            IARC MONOGRAPHS VOLUME 93

rocks, from which about 10% of world production is mined, and which is sometimes
found in combination with deposits of magnesium carbonate; the crude ore is generally
grey due to the presence of chlorite, but no upgrading is necessary as chlorite performs
adequately in the applications of interest.
    This wide diversity of origins and types of deposit naturally gives rise to a wide
variety of ores and product grades that differ according to their mineralogical
composition, colour and crystalline structure (microcrystalline or lamellar) (Luzenac,
2004; EUROTALC, 2005; Industrial Minerals Association-Europe, 2005).
    World production of talc and pyrophyllite in both 2003 and 2004 was estimated to be
8.3 million tonnes. Of the total production, approximately 2.15 million tonnes were
confirmed to be used for talc production in both 2003 and 2004. China was the leading
producer of talc in the world, followed by the USA, India, Brazil (crude) and France
(crude). The Republic of Korea was the leading producer of pyrophyllite, followed by
Japan and Brazil. Brazil, China, France, India, Japan, the Republic of Korea and the USA
produced 84% of talc and pyrophyllite in the world (Table 1.5) (Virta, 2004).

Table 1.5. World production of talc (in tonnes unless otherwise specified)a,b

Country                        2000         2001        2002        2003        2004

Argentina                           6730         1665        1643        1759        1800
Australiac                       178 545      173 446     173 741     174 000     173 000
Austria (crude+so)d              130 000e     140 000     135 000     135 000     135 000
Bhutand                            3700         3800        3900        3900         3900
Brazil (crude)                   300 000      397 000     348 000     365 000     370 000
Brazil (marketable product)f       7049         6300        5617        5593         5600
Canada (t+p+so)                   86 000       90 000      90 000      90 000      90 000
Chile                               2421         4177        3537        4374        4400
China (unspecified)d           3 500 000    3 500 000   2 500 000   3 000 000   3 000 000
Colombia (t+p+so)d                15 000       15 000      15 000      15 000      15 000
Egypt (t+p+so+st)d                40 000       40 000      40 000      40 000      40 000
France (crude)d                  350 000      350 000     350 000     350 000     350 000
Germany (marketable+st+t)d         8000        10 000      10 000      10 000      10 000
Hungaryd                             500          500         500         500         500
India (st)                       545 000      546 000     550 000     552 000     550 000
Irand,g                           25 000       25 000      25 000      25 000      30 000
Italy (t+st)d                    140 000      140 000     140 000     140 000     140 000
Japan                             50 000       45 000      40 000      40 000      35 000
Macedonia                            562          557         550         550         600
Mexico                            20 569       77 650     111 621     114 870     115 000
Morocco                           12 522       27 246      39 612        1959        2000
Nepalh                             5852         3923        2621        2500         2400
Norway (t+so+st)d                 27 000       27 000      28 000      28 000      28 000
North Korea (unspecified)d       120 000      120 000     110 000     110 000     110 000
Paraguay (t+p+so)d                   200          200         200         200         200
Peru                                9668       11 165      10 685      10 791      10 000
Portugald                          8200         8200        8200        8200         8000
Republic of Korea                 11 344       47 712      37 863      47 911      48 000
Romania                             7850         7270        7292      10 082      10 000
Russiad                          100 000      100 000     100 000     100 000     100 000
                                                       TALC                                                         289


Table 1.5 (contd)

Country                            2000             2001            2002             2003             2004

Slovakia                                1800             2600            2290             1000             1500
South Africa                            5600             3218            2511             4472           12 065e
Spain (t+st)d                        100 000          100 000         100 000          100 000          100 000
Sweden (t+so)                         20 000           15 000          15 000           15 000            14 000
Taiwan                                     –              130              27              466               411e
Thailand                                7390             6838            1702             8501              8500
United Kingdom (t+p+so)d               5000             5000            5000             5000              5000
USA                                  851 000          863 000         828 000          840 000          857 000e
Uruguay (t+p+so)                        2903             1694            1700             1700              1700
Zimbabwe                                 989             1273             911              196                 –e

From Virta (2004)
p, pyrophyllite; so, soapstone; st, steatite; t, talc
a
  World totals; data from the USA and estimated data are rounded to no more than three significant digits; may not
add to totals shown.
b
  Table includes data available through to April 19 2005.
c
  Data based on Australian fiscal year ending 30 June of the year stated.
d
  estimated
e
  Reported figure
f
  Direct sales and/or beneficiated (marketable product)
g
  Data based on Iranian fiscal year beginning 21 March of the year stated
h
  Data based on Nepalese fiscal year beginning mid-July of the year stated



1.2.2       Use
    The properties of mineral talc (platyness, softness, hydrophobicity, organophilicity
and inertness) and the mineralogical composition of talc products govern their specific
applications in many industries and processes including paint, polymers, paper, ceramics,
animal feed, rubber, roofing, fertilizers, cosmetics and pharmaceuticals. The principal
technical applications of talc in commercial products are as an anti-sticking and anti-
caking agent, lubricant, carrier, thickener, strengthening and smoothing filler and
absorbent (Industrial Minerals Association-Europe, 2005).

            (a)      End-use categories
                  (i)   Agriculture and food
    Talc is used as an anti-caking agent, dispersing agent and die lubricant in animal feed
and fertilizers. In premixes and agricultural chemicals, it is used as an inert carrier. Talc is
also used as an anti-stick coating agent in several foods and as a processing aid in the
production of olive oil. (Luzenac, 2004; Industrial Minerals Association-Europe, 2005).
    Agricultural chemicals. Talc is a functional carrier in agricultural products that offers
very low moisture equilibrium, relative hydrophobicity and chemical inertness. Costs are
reduced by extending expensive chemicals and improving the dispersion and flow of
290                         IARC MONOGRAPHS VOLUME 93

active ingredients. Talc is appropriate for garden dusts, flea and tick powders, seed
treatments and biocides (Luzenac, 2004).
     Anti-caking and homogenization. Talc improves the flowability of difficult raw
materials, e.g. oilseed meal and finished products, and feeds with high loads of sticky
ingredients such as molasses, oil, fatty products, urea, milk powder and sugar. The
smooth and flat lamellae of talc cover each particle and help them to flow freely. As they
are naturally water-repellent, talc particles form a barrier when they envelop other
particles and reduce the evaporation and uptake of water within the product mass. Talc
platelets help different constituents to blend more easily and facilitate the dispersion of
sticky ingredients (Luzenac, 2004).
     Die lubricant. Talc is a cost-effective die lubricant especially for high-fibre, high-
sugar and high-mineral formulations and pelleted feeds (Luzenac, 2004).
     Fertilizers. Talc is used as an anti-caking agent in both prilled (pelleted or granulated)
ammonium nitrate and granular fertilizers. Talc particles reduce the absorption of
moisture and prevent the formation of hydrate bridges, which enables longer storage
periods. In Europe, amine-coated talcs are marketed with enhanced adhesion properties
that enable the amine contents to be reduced and result in lower dust levels and less
environmental impact (Luzenac, 2004).
     Foods. Talc is an effective anti-stick coating agent that is used in several foods, such
as chewing gum, candies and cured meats (Luzenac, 2004).
     Processing of olive oil. In the production of olive oil, talc acts as a natural processing
aid that improves extraction and increases the yield of virgin olive oil (Luzenac, 2004).
     Premixes. Talc is used as an inert carrier for active premix ingredients. Certain talc
grades have been specifically designed for dust-free, high-specification requirements
(Luzenac, 2004).
                 (ii) Ceramics
    Talc imparts a wide range of properties to floor and wall tiles and sanitary ware,
tableware, refractory goods and technical ceramic products. In traditional building
ceramics (tiles and sanitary ware), it is used essentially as a flux to enable firing
temperatures and cycles to be reduced. In refractory applications, talcs that are rich in
chlorite are used to improve thermal shock resistance. Talcs with a microcrystalline form
are the most appropriate for steatite ceramics. During firing, the talc is transformed into
enstatite, which possesses electro-insulating properties. Talcs with a very low iron content
are particularly suitable for use in frit, engobe [underglaze] and glaze compositions
(Luzenac, 2004; Industrial Minerals Association-Europe, 2005).
                 (iii) Coatings
    Talcs confer several properties on coatings. In interior and exterior decorative paints,
they act as extenders to improve hiding power and the efficiency of titanium dioxide. The
lamellar platelets of talc make paint easier to apply and improve cracking resistance and
sagging, and also enhance matting. In anti-corrosion primers, talcs are used to improve
                                            TALC                                           291

resistance to corrosion and adhesion of the paint. They are also used in inks, jointing
compounds, putties and adhesives (Luzenac, 2004; Industrial Minerals Association-
Europe, 2005).
                  (iv) Paper
    Talcs are used in both uncoated and coated rotogravure papers in which they improve
printability, reduce surface friction and enhance handling characteristics. They also
improve mattness and reduce ink scuff on offset papers. When used as pitch-control
agents, talcs ‘clean’ the papermaking process by adsorbing any sticky resinous particles in
the pulp onto their platy surfaces, and thereby prevent the agglomeration and deposition
of these on the felts and calenders. In contrast to chemical pitch-control products that
pollute the process water, talc is removed with the pulp, which enables the papermaker to
operate more easily in a closed circuit. In specialty papers such as coloured papers or
labels, talcs help to improve quality and productivity (Luzenac, 2004; Industrial Minerals
Association-Europe, 2005).
                (v) Personal care
    As it is soft to the touch and inert, talc has been valued for centuries as a body
powder. Today, it also plays an important role in many cosmetic products, including
products for feminine hygiene and baby powders, and provides the silkiness in blushes,
powder compacts and eye shadows, the transparency of foundations and the sheen of
beauty creams. In pharmaceutical products, talc is an important excipient that is used as a
glidant, lubricant and diluent. Soap manufacturers also use talc to enhance the
performance of skin care products (Luzenac, 2004; Industrial Minerals Association-
Europe, 2005). Table 1.6 presents information on levels of talc in cosmetic products in the
USA and Table 1.7 gives the composition of some examples of products that are used for
body care.
                  (vi) Plastics
     Talcs impart a variety of properties to polypropylene, such as greater stiffness and
improved dimensional stability in automotive parts, household appliances and white
goods. Advanced milling technology is required to obtain the finest talcs without
diminishing the reinforcing power of their lamellar structure. Talcs are also used for the
anti-blocking of linear low-density polyethylene and as a nucleating agent in
semicrystalline polymers. In polypropylene that is used in food packaging applications,
talc is a highly effective reinforcing filler. The grades of talc used for this purpose include
calcined, surface-treated, ultrafine grind and high aspect ratio (Luzenac, 2004; Industrial
Minerals Association-Europe, 2005).
                (vii) Roofing
   Talc is a high-performance product that is used to back surfacing asphalt shingles.
The use of talc is even more important in the growing market for laminated shingles in
292                            IARC MONOGRAPHS VOLUME 93

which handling is more complex, wear and tear on machinery is greater, cutting is
doubled and adhesion of the interlayer is critical (Luzenac, 2004).

           Table 1.6. The number of cosmetic products in the
           Cosmetics and Toiletries Formulations Database in the
           USA that contain talc or talcum

           Product categories                                    No. of products

           Antiperspirants and deodorants                          22
           Baby products                                            6
           Bath and shower products                                 2
                       a
           Beauty aids                                           184
           Creams                                                  14
           Hair care products                                       1
           Lipsticks                                                5
           Lotions                                                  1
           Shampoos                                                 1
           Shaving products                                         2
           Sun care products                                        3
                           b
           Miscellaneous                                            8

           Compiled by the Working Group from Flick (2005)
           a
             Beauty aids includes aerosol talc products, face masks, foundations, body
           oils, make-up bases, concealers, blushes, body powders, rouge, make-up,
           compact powders, eye shadows, dusting powders, eyebrow pencils, pressed
           powder products, face powders, mascaras, liquid talc products and powder
           cleansers
           b
             Miscellaneous includes aerosol talc foams, wound ointments, foundations
           with extracts, foot powders, liquid foundations and sport tints


                 (viii) Rubber
    Talcs reduce the viscosity of rubber compounds and thereby facilitate the processing
of moulded parts. They also improve the quality of extrudates, which increases
production rates and enhances the resistance to ultraviolet (UV) radiation of exterior parts
such as automotive profiles. In sealants and gaskets, they provide compression resistance,
while in pharmaceutical stoppers, they create a barrier against liquids. Talcs are used as
insulators in cables and as processing aids in tyre manufacture (Luzenac, 2004; Industrial
Minerals Association-Europe, 2005).
                                        TALC                                   293


Table 1.7. Composition of some products used for body care

Product                  Wt% talc   Other components              Wt% other
                                                                  components

Dusting powder           97.7       Perfume oil                    0.8
                                    GLUCAM P-20                    1.5
                                    Preservative                  q.s.
Dusting powder           91.6       Magnesium carbonate            3.0
                                    Zinc stearate                  3.0
                                    Triclosan                      0.2
                                    Perfume oil                   0.7
                                    GLUCAM P-20                    1.5
                                    Preservative                  q.s.
Velvety dusting powder   77.4       Aluminum starch, Octenyl      20.0
                                    succinate
                                    Zinc stearate                  2.0
                                    Methylparaben                  0.10
                                    Propylparaben                  0.10
                                    Germall II                     0.20
                                    Fragrance                      0.20
Face and body powder     89.30      Boron nitride                 10.00
                                    Methylparaben                  0.15
                                    Propylparaben                  0.20
                                    Imidazolidinyl urea            0.05
                                    Iron oxide (yellow)            0.20
                                    Iron oxide (red)               0.10
Baby powder              72         DYNASAN 114                    2.0
                                    Magnesium stearate             8.0
                                    Kaolin                        18.0
After-bath talc          92.5       Perfume oil                    5.0
                                    PPG-20 methyl glucose ether    1.50
                                    Macadamia nut oil              1.00
Body powder               4.0       Boron nitride                  5.0
                                    Silica                         2.5
                                    Starch                        30.2
                                    Kaolin                        10.0
                                    Magnesium stearate             1.00
                                    Bentone 38/Quaternium18,       1.0
                                    Hectorite
                                    Isopropyl myristate            6.0
                                    Perfume                        1.8
                                    Pigments                      q.s
294                           IARC MONOGRAPHS VOLUME 93


Table 1.7 (contd)

Product                       Wt% talc    Other components                    Wt% other
                                                                              components

Powder for babies and         20.0        Kaolin                              20.0
children
                                          Rice starch                         51.0
                                          Zinc stearate                        5.0
                                          Eutanol G                            2.0
                                          Lanette O                            2.0
Dispersing bath powder        0           Kukui nut oil                         1.0
                                          Phenyl trimethicone                   1.0
                                          Cyclomethicone                        2.0
                                          Fragrance                             1.5
                                          Ethoxydiglycol                        2.0
                                          Oleth-2                               2.50
                                          Oleamidopropyl PG, dimonium           2.0
                                          chlorite
                                          Topopheryl acetate (Vitamin E)       0.50
                                          Cornstarch                          86.00
                                          Silica                               1.50
Body powder                   0           Zinc stearate                        5.0
                                          Zinc oxide                           5.0
                                          Magnesium carbonate                 15.0
                                          Kaopolite TLC                       75.0
Talc-free body powder         0           Cornstarch                          88.45
                                          Kaolin                               5.0
                                          Mica                                 2.0
                                          Titanium dioxide                     2.0
                                          Red mica and titanium dioxide        0.25
                                          Tapioca starch                       2.0
                                          Methylparaben                        0.10
                                          Propylparaben                        0.05
                                          Imidazolinidyl urea                  0.15

From Flick (2005)
The Working Group was aware that these data are not representative of all products
q.s., quantum satis (sufficient quantity)


                 (ix) Wastewater treatment
   Specialty talc can improve the performance of biological wastewater treatment plants.
The talc particles ballast the flocs of bacteria and accelerate their sedimentation (Industrial
Minerals Association-Europe, 2005).
                                          TALC                                          295

                 (x) Other
     Talc is used as an anti-sticking agent to powder moulds in foundries and in the
manufacture of pharmaceuticals and rubber or on conveyor belts that carry foodstuffs. It
is also used in other products, such as condoms and surgery gloves. Particle-wood boards
(chip boards) are powdered with talc to avoid sticking when stockpiled. Talcs are also
used as smooth fillers, for example in the ‘lead’ of colouring pencils and in putties (where
it can be the major component) (Industrial Minerals Association-Europe, 2005).
     Talc had been used as a sclerosing agent in the pleural space for the treatment of
spontaneous pneumothoraces. Talc is also used for pleurodesis in the treatment of
malignant pleural effusions (Dresler et al., 2005). The products used for these purposes
contain 95% talc and 5% chlorite and dolomite.

         (b)    Use patterns
    The worldwide use pattern for talc in 2000 was: paper, 30%; ceramics, 28%;
refractories, 11%; plastics, 6%; a filler or pigment in paints, 5%; roofing, 5%; cement,
3%; cosmetics, 2%; and other miscellaneous uses, 10% (art sculpture, asphalt filler,
autobody filler, construction caulks, agriculture and food, flooring and joint compounds)
(Roskill Information Services Ltd, 2003). The use pattern for talc in the USA in 2004
was: ceramics, 32%; paints, 19%; paper, 16%; roofing, 6%; plastics, 4%; rubber, 3%;
cosmetics, 1%; and other, 19% (Virta, 2004). The use of talc in cosmetics in the USA
decreased from 34 000 tonnes in 1993 to 5000 tonnes in 2004 (Virta, 2004).
    The estimated world consumption of talc by geographical region in 2000 was: Asia,
43%; western Europe, 19%; North and central America, 17%; South America, 8%; Indian
subcontinent and Middle East, 8%; Africa, 2%; eastern Europe and Commonwealth of
Independent States countries, 2%; and Australia and New Zealand, 1% (Roskill
Information Services Ltd, 2003).

1.3      Occurrence and exposure

1.3.1    Natural occurrence
    Talc is found in small amounts in metamorphic mafic and ultramafic rocks and in
carbonates. These metamorphic rocks crop out in mountain belts such as the Alps, the
Appalachians and the Himalayas and in ancient continental shields such as the Canadian
shield in New York and Canada.
    The occurrence of talc deposits of commercial importance is described extensively in
Section 1.1.4.

1.3.2    Occupational exposure
    Exposure to talc dust occurs during its mining, crushing, separating, bagging and
loading and in various industries that use talc (see Section 1.2.2). This section reviews
296                        IARC MONOGRAPHS VOLUME 93

exposure to talc during its mining and milling, other than that from the Gouverneur
District New York State mines, and in user industries, whenever this information is
available. Exposure to talc is also described, where possible, for those industries in which
epidemiological studies have been carried out in relation to the occurrence of cancer.

         (a)    Mining and milling
     Before the 1970s, exposure measurements were made by collecting particles in an
impinger and counting them by optical microscopy. Concentrations were thus expressed
as million particles per cubic foot of air (mppcf). More recent studies have described
levels of exposure to dust that were assessed using gravimetric measurement techniques.
     Table 1.8 describes studies of exposure to talc in mines and mills. In Georgia, USA,
average exposures to dust were 1440 mppcf (~50 854 particles/cm3) for miners who used
jackhammer drills and 52 mppcf (~1836 particles/cm3) for millers. The talc was reported
to contain 45% tremolite and 45% talc, with little or no quartz (Dreessen, 1933). Average
dust concentrations in a talc mine were reported to range from 32 to 855 mppcf (~1130 to
30 195 particles/cm3; six samples), whereas those in mills ranged from 17 to 1672 mppcf
(~600 to 59 000 particles/cm3; 14 samples). The dust was reported to contain 70% talc,
20–30% dolomite and 10% tremolite, and no quartz except for occasional fragments; its
morphology was described as ‘bladed crystals’. Highest exposures to dust occurred
during bagging operations (Dreessen & DallaValle, 1935).
     Concentrations of respirable dust in mass samples from three Vermont talc mines and
mills surveyed in 1975–76 are given in Table 1.9. Geometric mean exposures to
respirable dust ranged from 0.5 to 5.1 mg/m3 in the mines and from 0.5 to 2.9 mg/m3 in
the mills; however, exposures in the mills were generally higher than those in the mines.
Optical fibre counts as high as 60 fibres/cm3 were reported. Subsequent analyses of these
samples by scanning electron microscopy showed that they consisted of rolled talc and
elongated talc particles. X-Ray diffraction analyses of bulk samples from these mines and
mills showed that talc and magnesite were the major (20–100%) mineral components,
chlorite and dolomite were minor (5–20%) components and calcite, quartz, biotite,
ankerite, chromite, phlogopite and oligoclase were present in small amounts (<5%). Trace
amounts of quartz were found in 15% of the samples (Boundy et al., 1979). Dust from
one closed mine was reported to contain tremolite microinclusions, but its fibrosity was
not documented (Selevan et al., 1979).
     A cross-sectional study of occupational exposures in talc mines and mills in the USA
was conducted by the National Institute for Occupational Safety and Health; the results
are summarized in Table 1.10. Bulk samples from each region were analysed by
transmission electron microscopy: no fibre was found in any sample of Montana talc;
fibrous tremolite and antigorite were reported in Texan talcs (0.5–3.0 μm in diameter, 4–
30 μm in length); and talcs from North Carolina contained particles with length:diameter
ratios as high as 100:1, with some <0.1 μm in diameter (Greife, 1980; Gamble et al.,
1982). Van Gosen et al. (2004) recently reported that the Texan talc contained little or no
amphibole.
Table 1.8. Studies of occupational exposures in talc mines and mills

Reference                         Location of talc deposit     Date of exposure   Method of measurement     Other minerals present
                                                               measurements

Dreessen (1933)                   Georgia, USA                 Pre-1933           Impinger                  Tremolite
Dreessen & DallaValle (1935)      Georgia, USA                 Pre-1935           Impinger                  Tremolite, dolomite
Rubino et al. (1976); Coggiola    Piedmont, Italy              1946–95            –                         Quartz (radon, diesel exhaust)
et al. (2003)
Rubino et al. (1976)              Piedmont, Italy              1920–75            Impinger                  Small amounts of tremolite




                                                                                                                                             TALC
Boundy et al. (1979)              Vermont, USA                 1975–76            Optical and electron      Dolomite, calcite, magnesite,
                                                                                  microscopy fibre counts   chlorite, traces of other
                                                                                                            minerals
Greife (1980); Gamble et al.      Montana, Texas and           1977–80            Gravimetric               Varied by location studied
(1982)                            North Carolina,
                                  USA
Wild et al. (1995, 2002)          France, Austria              1986–92            Gravimetric (CIP          Quartz: France, <3%; Austria,
                                                                                  personal sampler)         <4%

CIP, capteur individuel de poussière [personal dust sampler]




                                                                                                                                             297
298                             IARC MONOGRAPHS VOLUME 93


Table 1.9. Concentrations (mg/m3) of respirable dust in Vermont talc mines
and mills

Company       Area                      Summer 1975                  Winter 1976
                                        No. of     Geometric mean    No. of        Geometric mean
                                        samples    (mg/m3)           samples       (mg/m3)

A             Underground mine          18         0.6               16            0.5
              Mill (1st shift)           4         1.7               13            1.7
              Mill (2nd shift)           6         0.5                3            1.5
B             Underground mine          15         1.5               23            0.9
              Mill (1st shift)          22         1.8               42            1.8
              Mill (2nd shift)          12         2.9               16            1.9
C             Underground mine          12         0.5               19            0.7
              Walk-in mine               7         1.2
              Walk-in mine                                             6           1.7
              Open-pit mine              2         5.1               –             –
              Mill No. 1 (1st shift)    12         0.9               20            1.1
              Mill No. 1 (3rd shift)     3         0.8                 4           1.4
              Mill No. 2 (1st shift)    11         1.0                 8           0.5
              Mill No. 2 (2nd shift)    13         0.8                 3           1.1

From Boundy et al. (1979)



    Table 1.10. Concentrations of respirable dust in 275 samples from talc
    mines and mills located in Montana, Texas and North Carolina, USA

    Samples                              Geometric mean (mg/m3)
                                         Montana             Texas              North Carolina

    From mines                           0.66 (0.47–0.92)a   0.45 (0.18–0.71)   0.14 (0.07–0.31)
    From mills                           1.1 (0.85–1.41)     1.56 (0.96–2.54)   0.26 (1.13–0.51)
    Bulk talc samples (% free silica)    <0.8                2.23               1.45

    Adapted from Greife (1980); Gamble et al. (1982)
    a
     In parentheses, 95% frequency interval

    Analysis of 362 personal samples of respirable dust collected over a full shift from
talc mines and mills by the Mine Safety and Health Administration in the USA showed
the median dust exposure to be 1.20 mg/m3; 90% of all exposures were <2.78 mg/m3
(National Institute for Occupational Safety and Health, 1979).
                                         TALC                                         299

     Before the adoption of technical preventive measures in 1950, exposures in the talc
operation in the Germanasca and Chisone Valley (Piedmont), Italy, were reported to be
approximately 800 mppcf [~28 250 particles/cm3] in the mines and 25 mppcf
[~883 particles/cm3] in the mills. Exposures in both areas were reduced to less than
10 mppcf [~353 particles/cm3] after 1965 when improved ventilation techniques and wet
drilling procedures were introduced. Mineralogical analyses of the footwall rocks
demonstrated that they contained quartz, muscovite, chlorite, garnet, calcite, magnesite
and small quantities of other minerals. In a few specimens of footwall rocks, a small
amount of tremolite was detected, but no other type of amphibole or chrysotile. Talc
specimens from these mines were found very commonly to contain chlorite, but no
amphibole or chrysotile minerals. The quartz content of powdered talc specimens was
generally below the detection limits of X-ray diffraction (Rubino et al., 1976). In recent
years, the mean exposure to respirable dust was 1.1 mg/m3 (range, 0.5–2.5 mg/m3), while
the mean exposure to talc alone was 1.0 mg/m3 (range, 0.3–2.0 mg/m3). The authors
stated that there was a remarkable difference in the amount of quartz in air dust in mines
and mills and within jobs in the mine between drilling and other occupations. This was
mainly due to the high content of quartz in footwall rocks, rather than to the absence of
quartz particles in talc minerals (Coggiola et al., 2003). [The Working Group noted that
the analytical methods were not described in detail and the mineral habit of the tremolite
was not documented.]
     Wild et al. (1995) reported on a survey of the respiratory health of workers in a
French talc producing factory. At this quarry, crude talc was extracted and transported
directly to the mill using an overhead cable. The extracted ore consisted of a mixture of
talc, chlorite, some dolomite (<3%), occasionally quartz (<3%) and traces of calcite,
apatite, pyrite and mica. Amphiboles were not detected. A total of 1440 personal samples
were taken between 1986 and 1991. The mean levels of exposure to respirable dust
ranged from 0.5 mg/m3 for secretaries, managerial staff and outdoor workers who handled
the railway wagons to 15 mg/m3 for site cleaning staff. In 1991, only one exposure group
of four maintenance workers was estimated to have a mean exposure in excess of
5 mg/m3. However, the probability of exceeding an exposure level of 5 mg/m3 was more
than 10% for most maintenance and some production workers. This was explained by the
high variability of exposure among maintenance workers; eight of 10 groups of workers
in the maintenance workshop had geometric standard deviations >3. Exposure was found
to be more homogeneous among the production workers. The authors claimed that the
introduction of centralized aspiration devices and new working procedures had resulted in
lower levels of exposure. Mean levels of exposure in the in the past were estimated to
have been up to 60 mg/m3, especially for workers storing jute bags of talc in wagons.
Before 1985, the highest levels of exposure to dust for site cleaning staff were estimated
to be 30 mg/m3; for sacking and drying, exposure levels in the workplace before
1975 were estimated to be 20 mg/m3.
     Wild et al. (2002) also provided some additional exposure information for three
Austrian mines and their respective mills in the Styrian Alps. The ore mined at one site
300                            IARC MONOGRAPHS VOLUME 93

(site B) consisted of a talc–chlorite mixture with gange [dead rock] inclusions of about
25% (mainly alumino-silicate rock). The gange was dumped in the mine so that the
milled product was talc–chlorite and contained between 0.5 and 4% quartz. At site C, the
material mined was a talc–dolomite aggregation with a medium talc content of 25%. The
amount of quartz in the end-product was below 1%. However, materials from certain
parts of this mine that were rich in dolomite could have contained 2–3% quartz. At site D,
a light greyish quartz–chlorite–mica schist (alumino-silicate rock that consisted of an
aggregation of more or less equal proportions of mica, chlorite and quartz) was mined and
milled. Analyses of dust from the lungs and lymph nodes of employees in the Austrian
talc industry confirmed the presence of quartz and the absence of amphibole and
serpentine (Friedrichs, 1987). Table 1.11 summarizes the levels of exposure reported in
the French and Austrian talc mines and associated mills.

 Table 1.11. Levels (mg/m3) of exposure to respirable dust in one French and
 two Austrian talc mines and associated mills

 Exposure         Occupation      Mine/mill            No. of    Mean       Range       Date
 group                                                 samples

 No exposure      Office          French talc quarry   168       0.2                    1986
                  workers
 Low exposure     Maintenance     French talc quarry   100       0.5–2.6    0.11–17     1986
 (<5 mg/m3)       workers,
                                  Austrian mine B      173                  0.02–4.61   1988–92
                  garage
                  mechanics,      Austrian mine C       33                  0.02–4.1    1991–92
                  production
                  workers with
                  dust
                  control/LEV
 Median           Recent          French mine A        193       3.5–25.6   0.21–134    NR
 exposure         production
                                  Austrian mines B      17                  6.5–19.6    NR
 (5–30 mg/m3)     workers
                                  and C
 High             Milling,        Austria                3                  73–159      End of
 exposure         maintenance,                                                          1980s
 (>30 mg/m3)      cleaning

 From Wild et al. (1995, 2002)
 LEV, local exhaust ventilation; NR, not reported

    Several samples were collected from a crushing, grinding and talcum powder packing
unit at a plant in Pakistan to measure different particle sizes (Jehan, 1984). In total, seven
1-hour samples were collected, one for total suspended particles (concentration,
6.14 mg/m3), one for particulate matter (PM) <10 µm (1.12 mg/m3), one for PM <7 µm
(1.93 mg/m3), one for PM <5 µm (0.40 mg/m3), one for PM <3 µm (0.26 mg/m3), one for
                                            TALC                                             301

PM <2 µm (0.05 mg/m3) and one for PM >1 µm (1.55 mg/m3). Further analyses of the
samples with PM <10 µm and <2 µm by scanning electron microscopy showed that the
fibre concentration was 0.25 fibres/cm3 and 0.12 fibres/cm3, respectively. Analyses by
polarized light microscopy indicated the presence of asbestiform tremolite, chrysotile and
anthophyllite in these samples.

         (b)      User industries
    Only limited information is available on exposures in secondary industries in which
talc is used or processed further. Results from some surveys are summarized in
Table 1.12.

   Table 1.12. Mineral composition of talc used for dusting in the rubber
   industry in the USA

   Reference            Location     Date      Mineral composition    Method of analysis

   Hogue & Mallette     Vermont      1943–48   Stated to be ‘pure     Impinger
   (1949)                                      talc’
   Dement & Shuler      Canton, MA   1972      2–3% quartz            Gravimetric, optical
   (1972)                                                             fibre counts
   Fine et al. (1976)   Vermont      1972–74   Trace of quartz        Gravimetric
                                               (<1%), <2 fibres/cm3


     Personal air samples collected in a rubber band production plant, where
housekeeping, ventilation and work practices were poor and talc was used as an anti-
sticking agent, had time-weighted average (TWA) concentrations of respirable dust of
2.5–7.8 mg/m3 (average, 4.8 mg/m3) for extruders, 5.3 and 6.1 mg/m3 for vulcanizers and
0.9 and 1.3 mg/m3 for cutters. Exposures to total dust were found to range from 5.4 to
199 mg/m3. The talc was reported to contain 2–3% quartz. Within these exposures, 4.7–
19.2 fibres were >5 μm/cm3 as measured by phase-contrast optical microscopy (Dement
& Shuler, 1972). [The Working Group noted that no electron microscopic analysis was
conducted to confirm the identity of the fibres; however, most of these were probably not
asbestos.]
     Concentrations of respirable dust in two rubber manufacturing plants where Vermont
talc was used as an anti-sticking agent are shown in Table 1.13. Eighteen of 21 samples
analysed for quartz contained less than 1% by weight. In 12 samples analysed for fibres,
using phase-contrast microscopic techniques for asbestos, all concentrations were less
than 2 fibres/cm3. No electron microscopic fibre analysis was reported (Fine et al., 1976).
Hogue and Mallette (1949) found an average dust concentration of 15–50 mppcf [~530–
1765 particles/cm3] talc in two rubber plants that used Vermont talc. Average exposures
were 20 mppcf [~706 particles/cm3] for tube machine operators, 35 mppcf
302                             IARC MONOGRAPHS VOLUME 93

[1236 particles/cm3] for tube ‘bookers’, 15 mppcf [~530 particles/cm3] for tube cure men
and 50 mppcf [~1765 particles/cm3] for ‘line rerollers’.

      Table 1.13. Concentrations of respirable dust in rubber processing
      plants that used talc

      Location                                  No. of      Average dust concentration
                                                samples     (mg/m3)

      Plant A
      Lorry and bus inner tubes (splicer)       7           0.60
      Lorry and bus inner tubes (cureman)       6           1.41
      ‘Tuber operator’                          3           0.47
      ‘Booker’                                  3           0.74
      Farm service inner tubes (splicer)        6           0.82
      Farm service inner tubes (cureman)        2           0.91
      Plant B
      Rubber band area                          6           3.55
      Gum engraving room                        6           0.64
      Hose extruding                            4           0.51
      Curing heavy duty flaps                   3           1.29
      ‘Dust room’                               2           0.59

      From Fine et al. (1976)

     In a mortality study of lung cancer and respiratory disease among pottery workers
exposed to silica and talc, Thomas and Stewart (1987) estimated exposure to non-
asbestiform talc and tremolitic talc. Exposure to talc occurred almost exclusively in the
cast shop. Montana steatite talc that had been used to dust moulds since 1955 appeared to
contain no asbestiform talc (Gamble et al., 1982; Grexa & Parmentier, 1979). However,
before 1955, flint and ground clay had been used to dust the moulds. Up to 1976,
tremolitic talc had been used in some glazes. No measurements of airborne talc or silica
were available, and exposure estimates were based on detailed knowledge of industrial
processes and job duties. All exposures to talc were associated with high exposure to
quartz from the clays. Quartz particles from clay are smaller than approximately 4 μm.
     Kauppinen et al. (1997) developed an international database of exposure
measurements in the pulp, paper and paper product industries. In total, 63 measurements
for talc were included in this database—four measurements in the pulp production and
59 in paper or paperboard production and recycling; 6% of the samples exceeded the
8-hour TWA threshold limit value (TLV) for talc of 2 mg/m3 respirable dust (ACGIH®
Worldwide, 2005). [No information was provided on the methods of measurement, the
time period when these measurements were taken or the actual processes and the
materials used during these measurements. As only a limited number of measurements
were available, it is improbable that these results are representative of exposure to talc in
this industry.]
                                            TALC                                            303

     Kauppinen et al. (2002) described the prevalence of exposure to talc among workers
in the on-machine coating of paper. In total, 25 departments were assessed: in 60% of the
departments, more than 5% of the workers were exposed to talc, with a median
prevalence of exposure of 51–90%. The median level of exposure was assessed as
medium (0.6–2 mg/m3) by a team of occupational hygienists.
     Pooley and Rowlands (1975) examined talc imported into the United Kingdom.
These talcs were used in a variety of industries, including cosmetics. Only one of the
samples examined contained tremolite (>30%). [The number of samples examined and
their use were not given. The electron micrograph of the sample identified as tremolite
and the concentration of tremolite are consistent with the Gouverneur District New York
State talc, which is unlikely to have been used in cosmetics.] All other elongated particles
detected in the samples were identified as laths or rolled sheets of talc, chlorite or sepiolite
(several samples).

1.3.3     Consumer exposure
          (a)    Mineralogical characterization
     Two studies that were conducted between 1968 and 1977 examined the mineralogy of
consumer talc in the USA.
     Cralley et al. (1968) examined 22 cosmetic talc products that were purchased off the
shelf for particles >5 μm with a 3:1 or greater aspect ratio (diameter:length) and found
that on average 19% of the particles met these dimensional criteria. [No additional
information was provided on the source of the talc products, but the Working Group
noted that the authors were located in Cincinnati, OH, USA.] The authors concluded that
these ‘fibres’ were predominantly talc, but suggested that some may have been
anthophyllite, tremolite, pyrophyllite or chrysotile. [The Working Group noted that no
data were provided to support this statement. The statement was based only on the fact
that these minerals have been reported to occur in some talc deposits.] Using X-ray
diffraction, quartz was found at a level of 0.2–53.4% in these samples. No limit of
detection was given, but the lowest concentration reported was 0.2 wt%. Analysis for
other minerals was not carried out.
     Rohl et al. (1976) examined 20 body powders, baby powders and facial talcums and
one pharmaceutical talc, all of which were purchased at retail stores in New York City
between 1971 and 1975. Based on X-ray diffraction, optical microscopy and transmission
electron microscopy, the concentration of tremolite, anthophyllite and quartz was
estimated and the presence of several other minerals was established (see Tables 1.14 and
1.15). One of the 21 samples was composed entirely of cornstarch and one contained
primarily pyrophyllite and only a small amount of talc. Quartz was present in nine of the
21 samples, tremolite was reported in nine, anthophyllite in seven and serpentine in two
samples. Chrysotile was confirmed by transmission electron microscopy in these samples,
but no estimates of the concentrations were provided. Krause (1977), in a review of this
study, pointed out that the overlap of the X-ray diffraction patterns of tremolite and
304                          IARC MONOGRAPHS VOLUME 93

anthophyllite makes accurate estimation of their concentration by this method impossible.
A similar problem was pointed out for estimates of the concentration of quartz because of
overlap with several talc peaks. [The Working Group believed that these criticisms were
reasonable and that little reliance can be placed on the reported concentration of tremolite
or anthophyllite. The Working Group also noted that Rohl et al. (1976) stated that their
methodology did not distinguish between asbestos and non-asbestiform mineral
fragments. In addition, the representativeness of these samples for other countries or for
other areas of the USA is unclear.]

            Table 1.14. Concentrations of minerals in 20 samples of
            body powders, baby powders and facial talcums and one
            sample of pharmaceutical talc

            Mineral                     No. of samples      Concentration range (wt%)

            Quartz                      9                   1.6–35.1
            Tremolitea                  9                   0.1–10.3
            Anthophyllitea              7                   2.1–11.4
            Chrysotile                  2                   <0.5b

            From Rohl et al. (1976)
            a
              Six samples contained both minerals, which resulted in uncertainty about
            the absolute concentrations given for each mineral.
            b
              Visual estimates by transmission electron microscopy were given as 0.25–
            0.5%, but no methodology was provided.



            Table 1.15. Qualitative measurements of minerals other
            than anthophyllite, chrysotile, quartz or tremolite in 20
            samples of body powders, baby powders and facial talcums
            and one sample of pharmaceutical talc

            Mineral                    No. of samples in which the mineral was present

            Talc                       20a
            Chlorite                   16b
            Calcite                     8b
            Phlogopite                  3b
            Pyrophillite                2b
            Dolomite                    1b
            Kaolin                      1b

            From Rohl et al. (1976)
            a
              Talc was the major mineral in 19 of the 20 samples.
            b
              Present in quantities above trace amounts
                                          TALC                                         305

    Paoletti et al. (1984) examined talc powders that were used in pharmaceutical and
cosmetic preparations. Tremolite was identified in two of six cosmetic talcs on the Italian
market. Six of 14 samples provide by the European Pharmacopoeia contained either
tremolite, anthophyllite or chrysotile. [No information was provided on the concentration
of minerals, including tremolite and quartz, or on the time of purchase.]
    Jehan (1984) reported on commercial cosmetic-grade talc (baby and body talcum
powder) used in Pakistan between 2000 and 2004. Sixty samples were analysed using
atomic absorption techniques, X-ray diffraction, polarized light microscopy and scanning
electron microscopy, and the presence of asbestiform chrysotile, both asbestiform and
non-asbestiform tremolite and anthophyllite was identified. Asbestiform varieties of
tremolite and anthophyllite were uncommon, while chrysotile was common. Respirable
quartz was also identified in most (80%) of the samples.
    Some products listed by the Cosmetic and Toiletries Formulations Database are
shown in Table 1.7. Listing is voluntary and may not be representative of products that
are on the market. Tables 1.16 and 1.17 present the average mineral composition of
commercial products that were sold under the name of talc in North America and Europe,
respectively, in the late 1980s.

         (b)    Use of talc for feminine hygiene
    The use of body powder for feminine hygiene can be estimated from the prevalence
reported for controls in case–control studies that investigated the association between the
use of cosmetic talc for feminine hygiene and the risk for ovarian cancer.
    The prevalence of ever use in these studies is summarized in Table 1.18. Higher
prevalences were generally reported in studies from Canada, the United Kingdom and the
USA (up to 59%), whereas the lowest prevalences were generally reported in studies
conducted in other countries, including China, Greece and Israel (2.2–5.6%).
    Studies with high prevalences also reported doses in terms of frequency, duration of
use, age at first use or cumulative doses. Frequency of use may vary from a few times per
month to more than once a day, and a large proportion of use is more or less daily.
Duration of use ranges up to more than 40 years. The cumulative exposure to talc by
perineal dusting was over 10 000 days in 4% of the users in one study (Cook et al., 1997).
The use of talcum powder for feminine hygiene is acquired in young adulthood, since
80% of women who use body powder start before the age of 25 years (Harlow & Weiss,
1989).
    The types of application also vary. Body powder can be applied perineally, on
napkins or on underwear. Dusting of the perineum after bathing appears to be the most
frequent single type of application, but simultaneous uses have also been reported.
Alternatively, exposure may occur as a result of storing a diaphram in body powder or
contamination from the male partner who has used body powder. One study in the USA
reported that the use of deodorant spray had a prevalence of 24% (Cook et al., 1997).
    In several of the studies in Table 1.18, the interviews on powder use occurred before
1988. Of these, all but one were conducted in the USA. Information on the composition
                                                                                                                                                 306
Table 1.16. Average mineralogical composition (%) of commercial products sold under the name of talc in North America

                     Canada                         Vermont                                     California   Texas   Montana          New York

Talc production      40 floated    10      30       70      30 floated    200      12 floated   10           307     326       20     140
(thousand tonnes)




                                                                                                                                                 IARC MONOGRAPHS VOLUME 93
Mineral (%)
Talc                 92.5          64.5    60.5     55      90            52.5     94.5         54           80      94         8     25
Chlorite              3            11.5    10.5      7       7             9        1.5          5            1       4.5      85.5
Dolomite              1             4       8        2       0.5           2        0.5          9           12.5     0.5      0.5
Magnesite             1.5          17      18       34       2            33.5      0.5         16                   T         T
Serpentine                                 T                                                                                          25
Quartz                                                                                                       T       T         T
Mica                 T             T                                                                         T       T         T
Calcite              T
Tremolite                                                                                                                             44
Anthophyllite                                                                                                                          5

From Ferret & Moreau (1990)
T, identified mineral that could not be measured by the methods of analysis used
Table 1.17. Average mineralogical composition (%) of commercial products sold under the name of talc in Europe

                 Finland                     Sweden      Norway      United Kingdom   France   Austria   Italy                        Spain
Talc             75 floated   250 floated    15          50          17               320      80        20      40     46     17     33      20     28
production
(thousand
tonnes)

Mineral (%)
Talc             93           88             64          55          54                59      51.5      51.5    86     51     47     89      80.5   53




                                                                                                                                                            TALC
Chlorite          3.5          8.5           16.5        11           9                39      42        43       9.5   19.5   22.5    6      12     18.5
Dolomite          0.5         T              11.5         2           2                 1.5     1         2       1.5   12     14.5    2       1.5    6
Magnesite         1.5          2                         29          30.5                       1                 0.5   10     14.5                  18.5
Serpentine                                                                                                              T      T
Quartz                                       T           T           T                         T         T              T                     T
Mica                                         T                                                 T         T                             1.5     1.5
Calcite                                      T           T                                               T              T              0.5    T
Tremolite                                    T

From Ferret & Moreau (1990)
T, identified mineral that could not be measured by the methods of analysis used.




                                                                                                                                                            307
                                                                                                                                                              308
Table 1.18. Assessment of exposure to body powders in the perineal area by women

Location               No. of     Prevalence of Type of perineal use of powder by women                                            Reference
                       controls   ever use
                                  of talc

Massachusetts, USA        215     28.4%         Exposure to talc by dusting                                                        Cramer et al. (1982)
Washington DC, USA        171      1.8%         Body talc                                                                          Hartge et al. (1983)
California, USA           539     45.8%         Use of talcum powder                                                               Whittemore et al. (1988)




                                                                                                                                                              IARC MONOGRAPHS VOLUME 93
United Kingdom            451     59.0%         Use of talc                                                                        Booth et al. (1989)
Washington, USA           158     40.5%         Exposure to powder (cornstarch, baby powder, talc, deodorizing powder); detailed   Harlow & Weiss (1989)
                                                information on type of powder used
Massachusetts, USA        239     39.3%         Exposure to baby powder, deodorizing or scented powder                             Harlow et al. (1992)
China                     224      2.2%         Dusting powder                                                                     Chen et al. (1992)
Maryland, USA              46     17.3%         Genital bath talc (also asked use on napkins or diaphragm)                         Rosenblatt et al.(1992)
Athens, Greece            193      3.6%         Local application of talc                                                          Tzonou et al. (1993)
Israel                    408      5.6%         Use of talc                                                                        Shushan et al. (1996)
Toronto, Canada           564     35.6%         Regular application of talc                                                        Chang & Risch (1997)
Washington, USA           422     39.3%         Dusting with cornstarch, talcum powder, baby or scented powder, and deodorizing    Cook et al. (1997)
                                                spray
New York, USA              50     26%           Use of talc                                                                        Eltabbakh et al. (1998)
Montreal, Canada          170      4.7%         Use of talc                                                                        Godard et al. (1998)
New England, USA          523     18.2%         Use of talc, baby or deodorizing powders or cornstarch                             Cramer et al. (1999)
New York, USA             693     35%           Use of talc (on genital or thigh area and sanitary napkins)                        Wong et al. (1999)
Delaware Valley, USA     1367     40%           Use of talc (on genital/rectal area and feet, sanitary napkins, underwear,         Ness et al. (2000)
                                                diaphragm/cervical cap, male partner user)
California, USA          1122     37.1%         Use of talcum powder                                                               Mills et al. (2004)
USA                    78 630     40.4%         Use of talc                                                                        Gertig et al. (2000)
                       cohort
                                          TALC                                         309

of baby powder, body powder, facial powder and pharmaceutical talcum powder on the
market in New York City before 1976 suggests that many of these products were impure
and contained anthophyllite, carbonate, chlorite, chrysotile, phlogopite, pyrophyllite,
quartz and tremolite (Cralley et al., 1968; Rohl et al., 1976). After 1976, these powders
probably did not contain anthophyllite, chrysotile or tremolite but may have contained up
to 10% of other minerals including carbonate, chlorite and quartz (Grexa & Parmentier,
1979). In 1994, baby talcum powder available in the USA typically contained 99% talc;
body powder typically contained 65–70% talc and the remaining material was cornstarch,
sodium bicarbonate and fragrance (Zazenski et al., 1995).

         (c)    Other uses of cosmetic talc
    Russell et al. (1979) and Aylott et al. (1979) reported exposure to respirable dust
during the use of talcum powders on the face, body and babies. Russell et al. (1979) took
48 measurements during baby dusting operations and 44 measurements during the
application of powders to adult bodies. Adult exposure was assessed during normal
face/body powdering practices by placing cyclone samplers on shelves at an appropriate
height or by positioning a cyclone attached to a headband near the nose (i.e. in the
breathing zone). Exposure to respirable dust was 2.03±1.48 mg/m3 during adult
application and was estimated to be 0.19 mg/m3 for babies. The estimated duration of the
application was 1.23 minute for adults and 0.52 minute for babies.
    Aylott et al. (1979) measured levels of exposure to respirable dust during the
application of loose face powder (24 measurements), adult dusting powder
(43 measurements) and baby dusting powder (32 measurements). In the study of baby
dusting powder, a doll was used. The exposure to respirable dust during face powdering
ranged from <0.1 to 1.7 mg/m3 (duration, 10–25 seconds), that for adult dusting powder
ranged from 0.2 to 3.3 mg/m3 (duration, 15–80 seconds) and that for baby powders
ranged from <0.1 to 0.9 mg/m3 (duration, 15–60 seconds).

         (d)    Other exposures
     Talc is used as a surface lubricant on the majority of condoms manufactured; contact
with condoms may also represent a direct means of exposure of the female genital tract to
talc (Kasper & Chandler, 1995).
     Exposure to talc can also occur during surgical procedures when using powdered
gloves. Talc particles were observed in the navels of small children, in the testes, on the
vocal cords, in the urinary bladder tract and after removal of varicous veins (Ramelet,
1991; Simşek et al., 1992). During breast implantations, it is possible that talc from
surgical gloves can lead to unwanted encapsulation (Chandler & Kasper, 2003).

1.3.4    Environmental exposure
    Talc is often detected as a common anthropogenic contaminant in suspended
sediment, even in remote snowfields in the Alps; this has been ascribed to its emission
310                          IARC MONOGRAPHS VOLUME 93

into the atmosphere by industrial and agricultural process (Hillier, 2001). Talc had also
been identified in the sediment of the River Don in Scotland (United Kingdom), although
no obvious industrial or agricultural sources of the talc were apparent (Hillier, 2001).

1.4           Regulations and guidelines

    Occupational exposure regulations and guidelines for talc in several countries are
presented in Table 1.19.

      Table 1.19. Occupational exposure standards and guidelines for talc

      Country or region    Concentration      Interpretation                  Carcinogenicity
                           (mg/m3)

      Australia            2.5                TWA
      Belgium              10 (I)             TWA
                           2                  TWA
      China                3 (T)              TWA
                           4                  STEL
      Canada
       Alberta             2 (R)              TWA
       British Columbia    2 (R)              TWA
       Ontario             2 fibres/cm3 (R)   TWA; value is for particulate
                                              matter containing <1%
                                              crystalline silica
       Quebec              3 (R)              TWA (talc–containing no
                                              mineral or asbestos fibres)
      Czech Republic       10 (R)             TWA; fibres >5%
                           2 (R)              TWA; fibres ≤5%
                           10 (T)             TWA
      Denmark              0.3 fibres/cm3     TWA; containing fibres          K
      Finland              5                  TWA
      Germany              (R)                MAK; without asbestos fibres    3B
      Hong Kong            2 (R)              TWA                             A4
      Ireland              10 (I)             TWA
                           0.8 (R)            TWA
      Japan                0.5 (R)            TWA
                           2 (T)              TWA
      Malaysia             2 (R)              TWA
      Mexico               2 (R)              TWA                             A4
      Netherlands          1 (R)              TWA
      New Zealand          2 (R)              TWA
      Norway               2 (R)              TWA
                           6 (T)              TWA
                                                 TALC                                                      311

   Table 1.19 (contd)

   Country or region         Concentration         Interpretation                     Carcinogenicity
                             (mg/m3)

   Poland                    1 (R)                 TWA
                             4 (I)                 TWA
   South Africa              1 (R)                 TWA
                             10 (I)                TWA
   Spain                     2 (R)                 Ceiling; containing no
                                                   asbestos fibres and <1%
                                                   crystalline silica
   Switzerland               2                     TWA
   United Kingdom            1 (R)                 TWA
   USA
    ACGIH (TLV)              2 (R)                 TWA; containing no asbestos        A4
    NIOSH (REL)              2 (R)                 and <1% crystalline silica
    OSHA (PEL)               ∼3 (20 mppcf)         TWA (10-h)
                                                   TWA; containing <1% quartz

   From Direktoratet for Arbejdstilsynet (2002); Työsuojelusäädöksiä (2002); SUVA (2003);
   ACGIH® Worldwide (2005); Deutsche Forschungsgemeinschaft (2005); Health and Safety
   Executive (2005)
   ACGIH, American Conference of Governmental Industrial Hygienists; I, inhalable dust; MAK,
   maximum concentration in the workplace; mppcf, millions of particles per cubic foot; NIOSH,
   National Institute for Occupational Safety and Health; OSHA, Occupational Safety and Health
   Administration; PEL, permissible exposure limit; R, respirable dust; REL, recommended
   exposure limit; T, total dust; STEL, short-term exposure limit; TWA, 8-h time-weighted average
   (unless otherwise specified)
   a
     3B, substances for which in-vitro test, or animal studies have yielded evidence of carcinogenic
   effects that is not sufficient for classification of the substance in one of the other categories; K,
   included in the list of substances considered as carcinogenic; A4, not classifiable as a human
   carcinogen

     The Food and Drug Administration regulates talc in the USA, and states that it is
generally recognized as safe for use in colour additives in foods, drugs and cosmetics, and
in paper, paper products, cotton and cotton fabrics that come into contact with food. The
Food and Drug Administration also states that talc is present in over-the-counter
astringent drug products (National Toxicology Program, 2000).
     The Food Chemical Codex (2003) provides specifications for food-grade talc,
including the statement that “talc derived from deposits that are known to contain
associated asbestos is not food grade.” Under the voluntary guidelines initiated in 1976,
the Cosmetic, Toiletry, and Fragrances Association stated that all cosmetic talc should
contain at least 90% platy talc (hydrated magnesium silicate) that is free from detectable
amounts (<0.5%) of fibrous, asbestos minerals (Gilbertson, 1995; Zazenski et al., 1995;
National Toxicology Program, 2000).
312                          IARC MONOGRAPHS VOLUME 93

    The current Occupational Safety and Health Administration (2005) permissible
exposure level for non-asbestiform talc in the USA is ~3 mg/m3 (20 mppcf) measured as
respirable dust. The current American Conference of Governmental Industrial Hygienists
TLV-TWA is 2 mg/m3 (15 mppcf), which also is the proposed Occupational Safety and
Health Administration limit. Levels of exposure of workers may exceed three times the
TLV-TWA for no more than 30 minute during the workday (National Toxicology
Program, 2000).

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                        2. Studies of Cancer in Humans

2.1      Occupational exposure

2.1.1    Talc miners and millers (Table 2.1)
     Rubino et al. (1976) conducted a study of mortality among men who had begun work
in the mines and mills of a talc operation in the Germanasca and Chisone valleys
(Piedmont), Italy, between 1921 and 1950 and who had been employed for at least 1 year
in a job that involved exposure to talc. A total of 1514 miners and 478 millers were
identified, of whom 168 miners (11.1%) and 40 millers (8.4%) were lost to follow-up
before the end of the study in June 1974, yielding a combined cohort of 1784 men
(89.6%) for analysis. The talc from these mines was described as pure and was reported to
have been used in the pharmaceutical and cosmetics industries. However, due to the
presence of ‘footwall contact rocks’ and rock-type inclusions in the mines, drilling
operations were associated with exposure to dusts that contained high levels of silica;
such inclusions were removed before milling and talc products were reported to have a
content of free silica below 2%. [The Working Group understood that the term ‘silica’
was in fact quartz.] In a few instances, talc samples from the area showed small amounts
of tremolite when examined by X-ray diffraction, but no amphibolic asbestos or
chrysotile were detected. For each worker, cumulative exposure was estimated from
regular measurements of respirable dust content in the air of mines and mills during the
period 1948–74 and individual work histories were abstracted from files of the mining
company. Periods of time during which the dust level was assumed to be uniform were
first selected and cumulative exposure was then calculated as the summed product of the
number of years in each specific working period (years) and the associated dust levels
(million particles per cubic foot; mppcf), resulting in an overall measure of mppcf–years.
Once individual cumulative exposures had been assigned, miners and millers were then
classified separately into low, medium and high levels of exposure. Ranges of exposure
(mppcf–years) for miners were 566–1699, 1700–5665 and 5666–12750, respectively;
ranges of exposure for millers were 25–141, 142–424 and 425–906, respectively. For
each of the 1784 workers included (1346 miners and 438 millers), one unexposed control
subject was chosen at random from among male inhabitants of a nearby small, rural town.
The control was matched to the talc worker on year of birth and vital status at date of
entry into the study [date not specified]. Cause of death for 885 (95.1%) of 931 deceased
workers and 1067 (94.8%) of 1126 deceased controls was obtained from regional death
certificate files supplemented with information from relatives, physicians and medical
records. Observed numbers of deaths among talc workers were compared with expected
numbers, calculated by the use of age-specific mortality rates experienced by the control
cohort. The standardized mortality ratio (SMR) for all causes combined was 0.9 (95%
Table 2.1. Cohort studies of mortality from and incidence of cancer in populations occupationally exposed to non-asbestiform talc

Reference,      Cohort              Exposure assessment         Organ site    Exposure categories     No. of   Relative risk   Adjustment factors;
location        description                                                                           cases/   (95% CI)        comments
                                                                                                      deaths

Rubino et al.   1992 male talc      Occupational history                                                       SMR
(1976),         workers (1514       from plant records;         All cancers   All miners              100      0.8 (0.6–0.9)   Adjusted for age;
Germanesca      miners, 478         respirable dust                           All millers              42      0.9 (0.7–1.2)   comparison with unexposed,
and Chisone     millers) employed   measurements, 1948–                                                                        age-matched controls from
valleys         >1 year in talc-    1974; quantitative                        Miners (mppcf–years)                             neighbouring rural town;
(Piedmont),     exposed job         estimation of cumulative                  Level 1: 566–1699        38      1.2 (0.8–1.6)   controls matched on vital
Italy           during 1921–        exposure for individual                   Level 2: 1700–5665       28      1.0 (0.7–1.4)   status at date of entry into
                1974; hired 1921–   workers, expressed as                     Level 3: 5666–12750      34      0.9 (0.6–1.2)   study;
                1950; mortality     summed product of                         Millers (mppcf–years)                            miners and millers exposed




                                                                                                                                                              TALC
                follow-up, 1921–    duration (years) and                      Level 1: 25–141          18      1.1 (0.2–3.2)   to a very pure form of talc;
                74; vital status,   exposure (million                         Level 2: 142–424         13      1.3 (0–2.9)     miners also exposed to
                90%; cause of       particles per cubic foot,                 Level 3: 425–906         11      0.7 (0.4–2.7)   inhalable silica;
                death: 95% of       mppcf); classification of                                                                  significantly elevated SMRs
                exposed workers,    workers into 3 levels of    Lung,        All miners                9       0.5 (0.2–0.9)   for silicosis with and
                95% of controls     exposure                    bronchus and All millers               4       0.6 (0.2–1.6)   without tuberculosis among
                                                                trachea                                                        miners; estimates increased
                                                                             Miners (mppcf–years)                              with increasing cumulative
                                                                             Level 1: 566–1699         3       1.1 (0.6–1.7)   exposure; no observed cases
                                                                             Level 2: 1700–5665        1       0.5 (0.7–2.3)   of mesothelioma;
                                                                             Level 3: 5666–12750       5       1.1 (0.4–1.3)   no smoking data for
                                                                             Millers (mppcf–years)                             exposed workers or
                                                                             Level 1: 25–141           3       1.7 (0.3–4.9)   unexposed controls
                                                                             Level 2: 142–424          1       1.25 (0–7.0)
                                                                             Level 3: 425–906          0       –




                                                                                                                                                              319
                                                                                                                                                                   320
Table 2.1 (contd)

Reference,       Cohort description    Exposure assessment        Organ site    Exposure categories     No. of   Relative risk      Adjustment factors;
location                                                                                                cases/   (95% CI)           comments
                                                                                                        deaths

Rubino et al.    1678 male talc        Same exposure                                                             SMR                Re-analysis of cohort
(1979),          workers (1260         categories as Rubino et    Lung          All miners              8        0.5 (0.2–0.9)      reported in Rubino et al.
Germanesca       miners,               al. (1976)                               All millers             4        0.7 (0.2–1.7)      (1976); SMRs recalculated
and Chisone      418 millers);                                                                                                      using national death rates




                                                                                                                                                                   IARC MONOGRAPHS VOLUME 93
valleys          mortality follow-                                              Miners (mppcf–years)                                instead of comparison with
(Piedmont),      up, 1946–74                                                    Level 1: 566–1699       2        0.5 (0–1.9)        neighbouring rural
Italy                                                                           Level 2: 1700–5665      1        0.2 (0.5–1.2)      population; national death
                                                                                Level 3: 5666–12750     5        0.6 (0.2–1.4)      rates available only from
                                                                                Millers (mppcf–years)                               1951 onward; rates for 1951
                                                                                Level 1: 25–141         3        2.0 (0.4–5.8)      were applied for 1946–50
                                                                                Level 2: 142–424        1        0.7 (1.7–3.7)
                                                                                Level 3: 425–906        0        –
Selevan et al.   392 white male        Historical insufficient                                                   SMR                Adjusted for age, sex, race,
(1979),          talc workers          information to calculate   All causes    Total cohort            90       1.2 [0.9–1.4]      calendar year; US death
Vermont,         (163 miners,          cumulative exposure                      Millers                 44       1.2 [0.9–1.6]      rates: 1940–67; linear
USA              225 millers)          histories; cohort                        Miners                  34       1.3 [0.9–1.8]      extrapolation for all causes
                 employed >1 year      classified into two work                                                                     of death: 1967–69.
                 between 1940 and      areas: mining and          All cancers   Total cohort            16       [1.3 (0.7– 2.0)]   Vermont death rates for
                 1969; mortality       milling.                                 Millers                  5       [0.8 (0.3–1.9)]    specific causes of death:
                 follow-up: date of                                             Miners                   7       [1.7 (0.7–3.5)]    1949–75; workers selected
                 first radiogram,                                                                                                   from annual radiographic
                 12-month                                         Respiratory   Total cohort                6    [1.6 (0.6–3.5)]    survey of dusty trades; no
                 employment                                       cancer        Millers                     2    [1.0 (0.1–3.7)]    data on smoking habits for
                 anniversary or                                                 Miners                      5    [4.3 (1.4–10.1)]   millers or miners; exposure
                 January 1940,                                                                                                      to radon daughters in mine;
                 whichever was                                                                                                      radiographic evidence of
                 later; follow-up                                                                                                   pneumoconiosis in most
                 through 1975; vital                                                                                                workers who died from non-
                 status: 99%; cause                                                                                                 malignant respiratory
                 of death: 94%                                                                                                      disease
Table 2.1 (contd)

Reference,     Cohort               Exposure assessment        Organ site    Exposure categories   No. of   Relative risk     Adjustment factors;
location       description                                                                         cases/   (95% CI)          comments
                                                                                                   deaths

Wergeland et   389 male talc-       Subjective assessment of                                                SMR               Adjusted for age, smoking
al. (1990),    exposed workers      exposure by experienced    All causes    Total cohort          117      0.8 (0.6–0.9)     (miners only); national
northern and   (94 miners,          colleagues; workers                      Miners                 27      [0.8 (0.5–1.2)]   death rates: 1953–87; main
western        295 millers)         classified by total                      Millers                90      [0.7 (0.6–0.9)]   minerals in mined talc
Norway         employed >1 year     duration of employment                                                                    deposit were talc and
               in mine (1944–       in jobs with low,          All cancers   Total cohort           26      0.8 (0.5–1.1)     magnesite; 90% of raw
               72) or >2 years in   medium, high and                         Miners                 9       [1.3 (0.6–2.5)]   material for mill from mine;
               mill (1935–72);      unknown exposure                         Millers                17      [0.6 (0.4–1.0)]   10% from India; no
               mortality and                                                                                                  information on smoking




                                                                                                                                                             TALC
               cancer incidence                                                                             SIR               habits for millers; smoking
               follow-up; 1953–                                All cancers   Total cohort           46      0.9 (0.7–1.2)     habits for miners above
               87                                                            Miners                 15      [1.4 (0.8–2.3)]   national average; low levels
                                                                             Millers                31      [0.8 (0.5–1.1)]   of exposure to radon
                                                                             Years employed                                   daughters
                                                                             1–4                    11      [1.1 (0.6–2.1)]
                                                                             5–19                   19      [0.8 (0.5–1.2)]
                                                                             >20                    16      [0.9 (0.5–1.5)]
                                                                             Years since first
                                                                             employment
                                                                             1–19                   6       [0.4 (0.2–0.9)]
                                                                             20–29                  18      [1.1 (0.7–1.8)]
                                                                             >30                    22      [1.1 (0.7–1.6)]




                                                                                                                                                             321
                                                                                                                                       322
Table 2.1 (contd)

Reference,     Cohort        Exposure assessment   Organ site   Exposure categories   No. of   Relative risk     Adjustment factors;
location       description                                                            cases/   (95% CI)          comments
                                                                                      deaths

Wergeland et                                       Lung         Total cohort          6        0.9 (0.3–2.0)
al. (1990)                                                      Miners                2        [1.6 (0.2–5.7)]




                                                                                                                                       IARC MONOGRAPHS VOLUME 93
(contd)                                                         Millers               4        [0.8 (0.2–2.0)]
                                                                Years employed
                                                                1–4                   0        –
                                                                5–19                  3        [1.0 (0.2–3.0)]
                                                                >20                   3        [1.0 (0.2–3.0)]
                                                                Years since first
                                                                employment
                                                                1–19                  2        [1.1 (0.1–4.1)]
                                                                20–29                 1        [0.5 (1.3–2.8)]
                                                                >30                   3        [1.1 (0.2–3.2)]

                                                   Stomach      Total cohort          6        1.1 (0.4–2.2)
                                                                Miners                3        [2.5 (0.5–7.4)]
                                                                Millers               3        [0.7 (0.1–2.1)]
                                                                Years employed
                                                                1–4                   2        [2.0 (0.2–7.2)]
                                                                5–19                  2        [0.8 (0.1–2.6)]
                                                                >20                   2        [1.2 (0.1–4.3)]
                                                                Years since first
                                                                employment
                                                                1–19                  1        [0.6 (1.4–3.1)]
                                                                20–29                 2        [1.1 (0.1–4.0)]
                                                                >30                   3        [1.7 (0.3–4.8)]
Table 2.1 (contd)

Reference,     Cohort               Exposure assessment           Organ site    Exposure categories          No. of   Relative risk   Adjustment factors;
location       description                                                                                   cases/   (95% CI)        comments
                                                                                                             deaths

Wild (2000),   1160 talc workers    Exposures assessed for                      Male talc workers                     SMR             Adjusted for age, sex,
Luzenac,       (1070 men, 90        case–control study; semi-     All causes    Pre-1968 (national rates)    101      0.8 (0.6–1.0)   smoking, prior exposure to
France         women) actively      quantitative, site-specific                 Post-1968 (national rates)   294      0.8 (0.7–0.9)   quartz (case–control study
               employed in 1945     job-exposure matrix                         Post-1968 (regional rates)   294      0.9 (0.8–1.0)   only); partial overlap of
               or hired during      based on personal dust                                                                            study population with
               1945–94 and          measurements (1986            All cancers   Post-1968 (regional rates)   80       1.0 (0.8–1.3)   Leophonte et al. (1983) and
               employed             onwards) and subjective                                                                           Leophonte and Didier
               >1 year; mortality   assessments by                Lung          Post-1968 (regional rates)   21       1.2 (0.8–1.9)   (1990); extent of overlap
               follow-up,,1945–     experienced workers;                        Post-1968 (national rates)   21       0.9 (0.6–1.4)   unknown; national mortality




                                                                                                                                                                      TALC
               96; vital status:    workers assigned to four                                                                          rates applied: pre- and post-
               97%; cause of        categories of exposure:                     Men <60 years of age         7        2.0 [0.8–4.0]   1968; regional mortality
               death: 74% pre-      no exposure, ambient                        Latency period <20 years     5        2.4 [0.8–5.6]   rates applied: post-1968:
               1968 and 98%         (<5 mg/m3), medium (5–                      Duration of employment       8        2.1 [0.9–4.1]   excess mortality from lung
               post-1968            30 mg/m3) and high                          <10 years                                             cancer disappeared when
                                    (>30 mg/m3); exposure                                                                             national rates applied
                                    prior to hiring also coded:   Stomach       Post-1968 (national rates)   5        1.2 (0.4–2.8)
                                    none, probable exposure
                                    to quartz, certain
                                    exposure to quartz,
                                    exposure to other
                                    carcinogens.




                                                                                                                                                                      323
                                                                                                                                                                    324
Table 2.1 (contd)

Reference,      Cohort                Exposure assessment           Organ site    Exposure categories   No. of   Relative risk   Adjustment factors; comments
location        description                                                                             cases/   (95% CI)
                                                                                                        deaths

Wild (2000)     Nested case–          Cumulative exposure           Lung                                         Odds ratio      Unadjusted odds ratio; no
(contd)         control study:        estimates (mg/m3–years)                     Unexposed              6       1.0             increasing trend with increasing
                lung cancer, non-     for individual workers.                     <100 mg/m3–years       5       1.4             cumulative exposure;
                malignant                                                         100–400 mg/m3–years    6       2.2             information on smoking habits
                pulmonary                                                         400–800 mg/m3–years    3       0.7             available for 52% of cases and




                                                                                                                                                                    IARC MONOGRAPHS VOLUME 93
                disease and                                                       >800 mg/m3–years       3       0.9             75% of controls
                stomach cancer;                                                                                                  Assumes a linear trend
                three randomly                                                    Per 100 mg/m3–years   23       1.0 (0.9–1.1)
                selected controls
                per case; lung
                cancer: 23 cases,
                67 controls
Wild et al.     Austrian cohort:      Austrian cohort: semi-                                                     SMR             Adjusted for age, calendar year,
(2002),         542 male talc         quantitative, site-specific   All causes    French cohort         294      0.9 (0.8–1.0)   smoking, exposure to quartz,
Luzenac,        workers               job-exposure matrix                         Austrian cohort        67      0.8 (0.6–1.0)   exposure to other carcinogens,
France          employed >1 year      based on personal dust                                                                     underground work (case–
(1 site), and   during 1972–95;       measurements (1988–92)        All cancers   French cohort          80      1.0 (0.8–1.3)   control study); study population
Styrian Alps,   mortality follow-     and descriptions of                         Austrian cohort        17      0.7 (0.4–1.2)   overlaps with that of Wild
Austria         up, 1972–1995;        workplaces from                                                                            (2000); French SMRs calculated
(4 sites)       vital status: 97%;.   management and long-          Lung          French cohort          21      1.2 (0.8–1.9)   by comparison with regional
                French cohort: as     term workers; workers                       Austrian cohort        7       1.1 (0.4–2.2)   rates, 1968–95; Austrian SMRs
                described under       assigned to four                                                                           calculated by comparison with
                Wild (2000)           categories of exposure:       Stomach       French cohort          5       1.2 (0.4–2.8)   regional rates, 1972–1995;
                                      no exposure, ambient (<5                    Austrian cohort        1       0.4 (0–2.3)     Austrian smoking information
                                      mg/m3), medium (5–30                                                                       obtained from unpublished
                                      mg/m3) and high (>30                                                                       mortality studies on
                                      mg/m3); other exposures                                                                    pneumoconiosis, from
                                      coded: quartz, other                                                                       colleagues, from workers’
                                      carcinogens, underground                                                                   compensation records; no
                                      work                                                                                       missing information on smoking
                                                                                                                                 habits in Austrian cohort
Table 2.1 (contd)

Reference,     Cohort               Exposure assessment         Organ site    Exposure categories          No. of   Relative risk    Adjustment factors;
location       description                                                                                 cases/   (95% CI)         comments
                                                                                                           deaths

Wild et al.    Nested case–         Cumulative exposure         Lung                                                Odds ratio      Unadjusted odds ratio; no trend
(2002) (contd) control study:       estimates (mg/m3–years)                   Unexposed                     9       1.0             observed with increasing
               lung cancer, non-    assigned to individual                    ≤100 mg/m3–years              6       0.9             cumulative exposure; trend not
               malignant            workers by occupational                   101–400 mg/m3–years           7       1.1             affected by adjusting for
               respiratory          physician using work                      401–800 mg/m3–years           5       0.6             smoking, quartz exposure,
               disease; three       histories abstracted from                 >801 mg/m3–years              3       0.7             underground work or by lagging
               randomly selected    company records                                                                                 the exposure estimate
               controls per case;                                             Per 100 mg/m3–years          30       1.0 (0.9–1.1)   Assumes a linear trend
               lung cancer: 23
               cases, 67 controls
               (France); 7 cases,




                                                                                                                                                                       TALC
               21 controls
               (Austria)
Coggiola et    Cohort of 1974       Detailed job histories                                                          SMR             Adjusted for age, calendar
al. (2003),    male talc workers    from plant records;         All causes    Total cohort                 880      1.2 (1.1–1.3)   period; study population
Piedmont,      employed >1 year     workers classified on                     Miners                       590      1.3 (1.2–1.4)   overlaps with that of Rubino et
Italy          in mine or mill      basis of job held (miner                  Millers                      290      1.1 (1.0–1.2)   al. (1976, 1979); national death
               during 1946–95;      versus miller), duration of All cancers   Total cohort                 185      1.0 (0.9–1.1)   rates used for pre-1970 period;
               mortality follow-    exposure (years) and time                 Miners                       130      1.1 (1.0–1.3)   rates for early 1950s used for
               up, 1946–95; loss    since first exposure                      Millers                       55      0.9 (0.6–1.1)   1946–49; regional rates used for
               to follow-up, 9%;    (years)                     Lung cancer   Total cohort                  44      0.9 (0.7–1.3)   1970–95, except for cancers of
               analysis based on                                              Miners                        33      1.1 (0.7–1.5)   oral cavity, oesophagus and
               1244 miners, 551                                               Millers                       11      0.7 (0.3–1.2)   suicide (regional rates
               millers                                                        Years since first exposure                            unavailable, national rates used
                                                                              <20                            6      1.1 (0.4–2.3)   ); no information on smoking
                                                                              20–30                         10      1.0 (0.5–1.8)   habits; no variation in lung
                                                                              >30                           28      0.9 (0.6–1.3)   cancer by duration of exposure




                                                                                                                                                                       325
                                                                                                                                                                         326
Table 2.1 (contd)

Reference,      Cohort               Exposure assessment          Organ site      Exposure categories          No. of     Relative risk   Adjustment factors; comments
location        description                                                                                    cases/     (95% CI)




                                                                                                                                                                         IARC MONOGRAPHS VOLUME 93
                                                                                                               deaths

Coggiola et                                                                                                               SMR
al. (contd)                                                       Oral cavity     Total cohort                   31       5.1 (3.5–7.3)
                                                                                  Miners                         24       6.2 (3.9–9.1)
                                                                                  Millers                         7       3.3 (1.3–6.9)
                                                                  Oesophagus      Total cohort                   10       2.1 (1.1–3.9)
                                                                                  Miners                          7       2.3 (0.9–4.8)
                                                                                  Millers                         3       1.8 (0.4–5.2)
                                                                  Stomach         Total cohort                   31       1.2 (0.8–1.6)
                                                                                  Miners                         20       1.2 (0.7–1.8)
                                                                                  Millers                        11       1.1 (0.5–2.0)

CI, confidence interval; mppcf, million parts per cubic foot; SIR, standardized incidence ratio; SMR, standardized mortality ratio
                                          TALC                                          327

confidence interval (CI), 0.8–1.0) for miners and 0.9 (95% CI, 0.8–1.0) for millers. No
relationship was observed with increasing time between first exposure and death or with
increasing cumulative exposure. Significant increases in specific cause of death among
miners were found for silicosis (62 observed; SMR, 2.0; (95% CI, 1.5–2.6) and for
silicosis with superimposed tuberculosis (18 observed; SMR, 2.0; 95% CI, 1.2–3.1).
These estimates were found to increase with increasing cumulative exposure. A total of
100 deaths from cancers at all sites combined among miners (SMR, 0.8; 95% CI, 0.6–0.9)
and 42 deaths among millers (SMR, 0.9; 95% CI, 0.7–1.2) were below those expected.
Nine deaths among miners (SMR, 0.5; 95% CI, 0.2–0.9) and four among millers (SMR,
0.6; 95% CI, 0.2–1.6) were due to lung cancer. No excess risk for lung cancer was found
in the highest exposure category among miners (cumulative exposure range, 5666–
12750 mppcf–years; five observed; SMR, 1.1; 95% CI, 0.4–2.7) or millers (cumulative
exposure range, 425–906 mppcf–years; no observed deaths versus 1.3 expected). No
cases of mesothelioma were found. [The Working Group noted that the lack of
comparability between the workers and the comparison groups could influence the
mortality ratio estimates of this study.]
     In a re-analysis of their 1976 study, Rubino et al. (1979) estimated relative mortality
among talc workers using Italian national death rates for men instead of the control
cohort. As national rates were available only for the period 1951–74 (end of the study),
rates for 1951 were applied for the follow-up period 1946 through to 1950. The number
of workers included in this analysis was 1260 miners and 418 millers. In contrast to the
previous analysis, the age-standardized mortality for all causes combined was
significantly increased for miners (560 observed; SMR, 1.3; 95% CI, 1.2–1.4) as well as
for millers (193 observed; SMR, 1.2; 95% CI, 1.0–1.4). Eight observed cases of lung
cancer in miners yielded an SMR of 0.5 (95% CI, 0.2–0.9) and four cases in millers
yielded an SMR of 0.7 (95% CI, 0.2–1.7). No trend was observed with increasing
cumulative exposure for either group of workers [p-value for trend not provided].
Mortality from non-malignant respiratory diseases was significantly increased among
miners (109 observed; SMR, 3.3; 95% CI, 2.7–4.0), mainly due to 58 cases of
pneumoconiosis and 23 cases of tuberculosis. The number of cases of pneumoconiosis
and tuberculosis among millers was three and eight, respectively.
     Katsnelson and Mokronosova (1979) conducted a study of mortality among male and
female workers [numbers not specified] in a talc mining and processing plant in the
former USSR in 1949–75. The talc of the area was reported to contain no tremolite or
fibrous materials and levels of quartz ranged from 0.2 to 1.6%. Very high mortality ratios
were found for cancer at all sites combined (relative risks, 5.1 for men; 6.4 for women;
P < 0.001) as well as for lung (relative risks, 4.5 for men; P < 0.02; 9.3 for women;
P > 0.05) and stomach cancer (relative risks, 3.7 for men; P < 0.02; 6.3 for women;
P < 0.05) [observed numbers of deaths not specified]. [The Working Group noted that the
deaths observed among exposed workers included current and past workers but that the
denominator comprised only currently employed persons.]
328                        IARC MONOGRAPHS VOLUME 93

     Selevan et al. (1979) used radiography records from the annual surveys of workers in
dusty trades of the Vermont Health Department to identify all white male workers
employed in the Vermont talc industry for at least 1 year between 1940 and 1969. The
study covered three areas that had a total of five companies (two of which ceased
operations in 1952 and 1960). The talc in this region is a mixture of pure talc, magnesite,
chlorite and dolomite. Airborne dust samples and bulk materials were free of asbestiform
minerals, when examined by both X-ray diffraction and analytical electron microscopy.
Levels of respirable crystalline silica were below 0.25% in nearly all ore and product
samples, and free silica was only occasionally detectable in air samples. Insufficient
information was available to estimate cumulative lifetime exposures, but the authors
stated that historical data were sufficient to demonstrate past exposure levels for miners
and millers far exceeded the standard for non-fibrous talc of 20 mppcf that was in force at
the time of the investigation. Due to the more continuous nature of the milling operation,
it was considered probable that exposures to dust for millers were higher than those for
miners. In one mine that had closed by the time of the study, ‘cobblestones’ of highly
tremolitic serpentine rock were present but were avoided or discarded as far as possible
before milling. Miners were also exposed to radon daughters at mean levels ranging up to
0.12 working levels (WL), with single peaks of 1.0 WL. The study groups comprised
163 talc miners and 225 millers. Vital status of workers was ascertained through to 1975,
and death certificates were obtained for 85 of 90 deceased cohort members. For non-
malignant respiratory disease and respiratory cancer, mortality rates for white men from
Vermont were used for comparison, because they were considered to be more appropriate
than national rates. For other causes of death, rates for the USA were used. Some increase
was noted for all malignant neoplasms combined (16 observed [SMR, 1.3; 95% CI, 0.7–
2.0]) and specifically for respiratory cancer (six observed [SMR, 1.6; 95% CI, 0.6–3.5]).
[The Working Group noted that the results for respiratory cancer were not analysed by
latency.] The excess mortality from respiratory cancer was statistically significant among
the miners (five observed [SMR, 4.3; 95% CI, 1.4–10.1]), but not among the millers (two
observed [SMR, 1.0; 95% CI, 0.1–3.7]). A significant excess of mortality from non-
malignant respiratory disease was seen in millers (seven observed [SMR, 4.1; 95% CI,
1.6–8.4]), but not in miners (two observed [SMR, 1.6; 95% CI, 0.2–5.9]). Most workers
who died from non-malignant respiratory disease had radiographic evidence of
pneumoconiosis (rounded opacities).
     In two brief communications, Leophonte et al. (1983) and Leophonte and Didier
(1990) reported on the mortality of workers employed in a talc quarry in Luzenac in the
South of France and in the associated talc processing plant. The cohort was composed of
those who left employment between 1945 and 1981 and who had worked at the plant for
more than 1 year. The talc in this region is a mixture of pure talc, chlorite and dolomite
with no asbestos; levels of quartz vary from 0.5 to 3%. Of 470 workers available for
study, 256 were alive, 209 had died and five were lost to follow-up. Of 204 workers with
a known job history and date of death, 192 had worked exclusively with talc at Luzenac.
No significant excess of mortality from cancer in general or specifically from respiratory
                                           TALC                                          329

and digestive cancers was found. [Observed and expected numbers of cause-specific
deaths and associated relative risks were not given.] A significant increase in mortality
was found for non-malignant respiratory disease, especially for pneumoconiosis and
obstructive lung disease. No cases of mesothelioma were observed. [The Working Group
noted the unconventional definition of the cohort and that causes of death were obtained
differently for cases (from local doctors, hospitals or families) and controls (from regional
or national records).]
     Wergeland et al. (1990) studied 94 male workers at a talc mine in northern Norway
who had been employed in talc-exposed jobs for at least 1 year during 1944–72 and
295 male workers at a talc mill in western Norway who had been employed for at least
2 years during 1935–72. Data on miners were gathered from the company pay rolls, lists
of union memberships and the central registry of workers exposed to silica in Norway;
data on millers were collected from the company protocol and the local occupational
health service. The information included name, date of birth, first and last date of
employment and number of periods of employment. According to the authors, Norwegian
talc contains only trace quantities of quartz, tremolite and anthophyllite as determined by
optical microscopy and by electron microscopic analysis. The talc in the region where the
mine was located is composed mainly of pure talc and magnesite. Approximately 90% of
the raw material in the mill came from the mine and the rest was imported from India. In
addition to talc, dolomite and mica were also processed at the mill. Personal air samples
collected in the early 1980s showed that total dust levels varied greatly by job category
and workplace (mine, 0.9–97 mg/m3; mill, 1.4–54 mg/m3). Peak exposures occurred
during drilling in the mine (319 mg/m3) and in the store house in the mill (109 mg/m3).
X-Ray diffractometry indicated that dust samples from both operations contained less
than 1% quartz. The mean value for concentrations of radon daughters in the mine was
3.5 pCi/L [0.04 WL], with a range of 1.5–7.5 pCi/L [0.02–0.08 WL]. The majority of the
389 workers could be classified into one of three categories according to degree of dust
exposure, based on measurements and qualified assessments of dust level by experienced
co-workers. Information on tobacco smoking habits, gathered during the study in 1981,
was available for 63 of the 94 miners and showed that smoking rates among these
workers were above the national average. Follow-up for cancer incidence (through data
linkage to the national cancer registry) and cause-specific mortality (through linkage to
the national mortality files) was begun at the date of entry into the cohort or 1 January
1953, whichever came later, and ended at date of death or 31 December 1987, whichever
came first. National rates were used to calculate expected numbers of cancers and deaths.
The SMR for all causes for the total cohort was 0.8 (117 observed; 95% CI, 0.6–0.9),
which reflected a decrease among both miners (27 observed [SMR, 0.8; 95% CI, 0.5–
1.2]) and millers (90 observed [SMR, 0.7; 95% CI; 0.6–0.9]). An excess of deaths from
all cancers was observed in miners (nine observed [SMR, 1.3; 95% CI, 0.6–2.5]), but not
in either the total cohort (26 observed [SMR, 0.8; 95% CI; 0.5–1.1]) or in millers
(17 observed; [SMR, 0.6; 95% CI; 0.4–1.0]). Mortality from non-malignant respiratory
diseases was decreased, with one observed death among miners [SMR, 0.4; 95% CI, 0–
330                       IARC MONOGRAPHS VOLUME 93

2.2] and two observed deaths among millers [SMR, 0.2; 95% CI, 0–0.9]. No deaths from
pneumoconiosis were reported. The standardized incidence ratio (SIR) for all types of
cancer combined was [1.4 (15 observed; 95% CI, 0.8–2.3)] among the miners and
[0.8 (31 observed; 95% CI, 0.5–1.1)] among the millers. Two cases of lung cancer were
observed among miners [SIR, 1.6; 95% CI, 0.2–5.7] and four cases among millers [SIR,
0.8; 95% CI, 0.2–2.0]. The non-significant excess risk among the miners was confined to
cancer of the stomach (three observed [SIR, 2.5; 95% CI, 0.5–7.4]) and cancer of the
prostate (four observed [SIR, 2.0; 95% CI, 0.6–5.2]). In the subgroup of 80 workers who
belonged to the highest exposure category, a total of six cases of cancer were observed
[SIR, 0.4; 95% CI, 0.2–1.0], none of which were cancer of the lung. There were no
observed cases of mesothelioma.
     Wild (2000) conducted a retrospective cohort mortality study, within a nested case-
control study, at the same talc quarry and milling plant at Luzenac as that used by
Leophonte et al. (1983) and Leophonte and Didier (1990). The cohort included
employees who were active in 1945 or hired in the milling plant during the period 1945–
94 and who had been employed continuously for at least 1 year. Employees, who were
identified from the company files, comprised a total of 1070 men and 90 women. [The
authors did not indicate the extent of overlap of the study population with that
investigated by Leophonte et al. (1983) and Leophonte and Didier (1990).] Dust levels in
the 1960s and 1970s were generally high, ranging from below 5 mg/m3 to more than
30 mg/m3. Average dust levels dropped to below 5 mg/m3 in the 1990s through process
changes and installation of engineering controls (e.g. installation of a central vacuum
system). Overall mortality of the cohort was evaluated from 1 January 1945 to
31 December 1996. Vital status was obtained from the local population register and
national mortality files which also included information on cause of death, in most cases,
for individuals who died after 1968. Overall, 32 (2.8%) employees were lost to follow-up.
Of 106 individuals who died before 1968, cause of death was ascertained for 78 cases.
SMRs were calculated using both regional mortality rates (pre- and post-1968) and
national mortality rates (pre-1968). When regional mortality rates for 1968 and later were
used, the SMR for all causes of death combined was 0.9 (294 observed; 95% CI, 0.8–1.0)
for men and 0.8 (11 observed; 95% CI, 0.4–1.4) for women. Eighty men died from cancer
at any site (SMR, 1.0; 95% CI, 0.8–1.3) and 21 died from lung cancer specifically (SMR,
1.2; 95% CI, 0.8–1.9). Mortality from lung cancer was non-significantly increased in
subgroups of employees who were under 60 years of age (seven observed; SMR,
2.0 [95% CI, 0.8–4.0]), had a latency period of less than 20 years (five observed; SMR,
2.4 [95% CI, 0.8–5.6]) or had a duration of employment of less than 10 years (eight
observed; SMR, 2.1 [95% CI, 0.9–4.1]). A slightly increased risk was seen for stomach
cancer (five observed; SMR, 1.2; 95% CI, 0.4–2.8). Twenty-six men died from non-
malignant respiratory diseases (SMR, 1.1; 95% CI, 0.7–1.6), three of which were
pneumoconiosis (SMR, 5.6; 95% CI, 1.1–16.2). When pre-1968 national reference rates
were applied, the overall SMR for men was 0.8 (101 observed; 95% CI, 0.6–1.0) and the
excess mortality from lung cancer and non-malignant respiratory diseases disappeared. Of
                                          TALC                                         331

the 101 deaths observed during this period, one was caused by lung cancer (SMR,
0.3 [95% CI, 0.7–1.5]) and five were caused by non-malignant respiratory diseases
(SMR, 0.7 [95% CI, 0.2–1.6]). A nested case–control study was performed to investigate
further the risks for lung cancer, stomach cancer and non-malignant respiratory diseases
in the men of the cohort. For the lung cancer case–control study, 67 controls were
individually matched to the 22 cases by age and sex (approximately three controls per
case). Information on job history at the plant and tobacco consumption was collected
through interviews of subjects who were alive and/or from experienced co-workers. A
semiquantitative site-specific job–exposure matrix for talc dust was established using dust
levels measured from 1986 onwards and estimates of levels before that year. Information
on job history was then converted into estimates of cumulative exposure of the individual
employees (expressed as mg/m3–years). Multiple logistic regression analysis with
adjustment for tobacco smoking habits and exposure to quartz estimated the odds ratio for
lung cancer to be 0.7 (three cases and 15 controls) and 0.9 (three cases and 10 controls)
for employees with a cumulative exposure to talc dust of 400–800 mg/m3–years and more
than 800 mg/m3–years, respectively, when compared with unexposed employees (six
cases and 20 controls). [The Working Group noted that information on smoking habits
was available for only 52% of cases and 75% of controls, and that no specific information
was given on the proportion of subjects alive among cases and controls at the date of
interview.]
    Wild et al. (2002) conducted a combined analysis of previously published cohort
mortality studies among 1070 male employees at a talc quarry and milling plant in the
south of France (Site A) (Wild, 2000) and 542 male employees at three talc mines and
their respective mills in Austria (Sites B, C and D). The Austrian cohort comprised
workers who had been employed for at least 1 year between 1 January 1972 and
31 December 1995. Complete work histories for the Austrian workers were abstracted
from company registries and from the regional social insurance. Information on tobacco
smoking habits was obtained from earlier unpublished studies of mortality and
pneumoconiosis, from colleagues and from records of the compensation claim insurance.
Talc from two of the three Austrian plants (Sites B and C) had a content of quartz that
was less than 4%, while that of the third plant (Site D) had higher but unspecified levels.
Vital status of workers was verified through to 1995, and cause of death for those who
had died was obtained from national mortality files. Local mortality rates yielded an
overall SMR for the Austrian cohort of 0.8 (67 observed; 95% CI, 0.6–1.0;). A total of
17 deaths were due to cancer at any site (SMR, 0.7; 95% CI, 0.4–1.2), seven of which
were from cancer of the lung (SMR, 1.1; 95% CI, 0.4–2.2). One death from stomach
cancer (SMR, 0.4; 95% CI, 0–2.3) and no deaths from mesothelioma (0.1 expected)
occurred. On the basis of 23 lung cancer deaths observed in the French cohort in 1968–
96 and seven in the Austrian cohort in 1972–95, a nested case–control study was
conducted. A total of 88 control subjects were selected from the two cohorts, individually
matched to cases on age, calendar period and company. All job tasks at the companies
were categorized according to measured and estimated levels of talc dust into one of four
332                        IARC MONOGRAPHS VOLUME 93

exposure groups (no exposure, < 5 mg/m3, 5–30 mg/m3 and > 30 mg/m3). Job histories of
cases and controls were converted into cumulative exposure to talc dust by summing the
products of duration and level of exposure for each of the tasks held by the subject
(mg/m3–years). Subjects were also categorized according to tobacco smoking habits,
exposure to quartz or a history of underground work on a yes/no basis. Information on
smoking habits was available for approximately 50% of the cases and 75% of the controls
in the French cohort and for 100% of the Austrian cohort. When the no-exposure category
was used as the standard (nine cases, 23 controls), the unadjusted odds ratios for lung
cancer were as follows: 0.9 (exposure category, 1–100 mg/m3–years; six cases,
18 controls); 1.1 (exposure category, 101–400 mg/m3–years; seven cases, 15 controls),
0.6 (exposure category, 401–800 mg/m3–years; five cases, 21 controls) and 0.7 (exposure
category, > 801 mg/m3–years; three cases, 10 controls). Assuming a linear trend, the odds
ratio was 1.0 (95% CI, 0.9–1.1) per unit of 100 mg/m3–years. Adjustment for tobacco
smoking, exposure to quartz or underground work or any two of these variables did not
change the results.
     Coggiola et al. (2003) updated the cohort of Rubino et al. (1976, 1979) to include
1974 men who had worked for at least 1 year in the mine and/or in the factory during the
period 1946–95. The mortality analysis included 1795 subjects (90.9% of the total cohort;
1244 miners and 551 millers), after excluding 179 workers who were lost to follow-up.
No data on smoking habits were available. Follow-up began on 1 January 1946 or the
date of first employment and ended at the date of death or 31 December 1995, during
which time a total of 880 deaths occurred. The expected number of deaths was calculated
from national rates for 1950–69 and regional mortality rates for 1970 onwards (with the
exception of cancers of the oral cavity and oesophagus for which regional rates were
unavailable; national rates were therefore used). Rates for the early 1950s were applied
for the period 1946–49. Total mortality among workers was higher than expected
(880 observed; SMR, 1.2; 95% CI, 1.1–1.3), mainly due to excess mortality from non-
malignant respiratory tract diseases among the subgroup of miners (105 observed; SMR,
3.1; 95% CI, 2.5–3.7). Of the 105 deaths in this category, 58 were from silicosis. In the
combined cohort of workers, there was no excess mortality for all cancers (185 observed;
SMR, 1.0; 95% CI, 0.9–1.1) or for lung cancer, in particular (44 observed; SMR, 0.9;
95% CI, 0.7–1.3). No deaths from pleural or peritoneal mesothelioma were found. A
significantly elevated risk was seen for cancers of the oral cavity (31 observed; SMR, 5.1;
95% CI, 3.5–7.3) and the oesophagus (10 observed; SMR, 2.1; 95% CI, 1.1–3.9). When
the analysis was stratified by job, the SMR for lung cancer was 1.1 (33 observed; 95% CI,
0.7–1.5) among miners and 0.7 (11 observed; 95% CI, 0.3–1.2) among millers. The slight
excess found among miners seemed to be due to a slightly elevated risk in workers with
less than 20 years since first exposure (latency) (six observed; SMR, 1.1; 95% CI, 0.4–
2.3) compared to that of workers with 20–30 years (10 observed; SMR, 1.0; 95% CI, 0.5–
1.8) and more than 30 years (28 observed; SMR, 0.9; 95% CI, 0.6–1.3) since first
exposure. There was no variation in lung cancer mortality by duration of exposure.
Cancer of the oral cavity caused the death of 24 miners (SMR, 6.2; 95% CI, 3.9–9.1) and
                                            TALC                                           333

seven millers (SMR, 3.3; 95% CI, 1.3–6.9) and oesophageal caused the death of seven
miners (SMR, 2.3; 95% CI, 0.9–4.8) and three millers (SMR, 1.8; 95% CI, 0.4–5.2).
Excess mortality was seen in miners for non-malignant respiratory tract diseases
(105 observed; SMR, 3.1; 95% CI, 2.5–3.7), non-malignant digestive tract diseases
(50 observed; SMR, 1.4; 95% CI, 1.0–1.8) and liver cirrhosis (37 observed; SMR, 1.8;
95% CI, 1.3–2.5). An increased risk for liver cirrhosis was also observed in millers
(18 observed; SMR, 1.7; 95% CI, 1.0–2.7).

         Meta-analysis of risk for lung cancer
     Wild (2006) performed a meta-analysis of lung cancer mortality among miners and
millers from industries that produced non-asbestiform talc in Vermont, USA (Selevan et
al., 1979), Norway (Wergeland et al., 1990), Italy (Coggiola et al., 2003), France (Wild,
2000) and Austria (Wild et al., 2002). The purpose of the analysis was to compute risk
estimates separately for talc miners, who usually have some co-exposure to silica and/or
radon daughters, and talc millers, who normally have no such co-exposure. Previously
unpublished risk estimates for the subgroup of millers in the French and Austrian cohorts
were used and additional information on smoking habits was obtained for Italian, French
and Austrian workers. Data indicated that the prevalence of smoking was higher than that
in the reference populations [figures not specified]. In the estimation of the overall risk for
millers, data from all five countries were used, while only data from the USA, Norway
and Italy were included in that for miners. Based on SMRs for lung cancer of 1.0 (USA;
two cases; 95% CI, 0.1–3.7), 0.7 (Italy; 11 cases; 95% CI, 0.3–1.2), 1.2 (France; 21 cases;
95% CI, 0.8–1.9), 0.7 (Austria, Site B; three cases; 95% CI, 0.1–2.0) and 1.1 (Austria,
Site C; one case; 95% CI, 0–6.2) and an SIR of 0.8 (Norway; four cases; 95% CI, 0.2–
2.0) for talc millers, a summary SMR of 0.92 (42 cases; 95% CI, 0.7–1.3) was obtained.
No heterogeneity between studies was detected. Similarly, based on mortality ratios for
lung cancer of 4.4 (USA; five cases; 95% CI, 1.4–10.2) and 1.1 (Italy; 33 cases; 95% CI,
0.7–1.5) and an incidence ratio of 1.6 (Norway; two cases; 95% CI, 0.2–5.7) for talc
miners, a summary SMR of 1.2 (40 cases; 95% CI, 0.9–1.6) was found. Due to a
significant heterogeneity of the latter data set, a random effect estimate of the overall
SMR was also calculated (40 cases; SMR, 1.9; 95% CI, 0.7–5.1).

2.1.2    User industries (Table 2.2)
    Information on risk for cancer among workers exposed to talc is available from
studies that were conducted in user industries. However, they are less informative than
those conducted in talc miners and millers because the potential contamination of talc was
not addressed. In addition, these studies provided no details about the type of talc used.

         (a)    Manufacture of ceramic plumbing fixtures
   Thomas and Stewart (1987) conducted a cohort mortality study of 2055 white men
employed for at least 1 year between 1939 and 1966 at three plants of a single company in
                                                                                                                                                                  334
Table 2.2. Cohort studies of mortality from and incidence of cancer in workers occupationally exposed to non-asbestiform talc
in user industries

Reference,      Cohort               Exposure assessment        Organ site     Exposure categories        No. of   Relative risk    Adjustment factors;
location        description                                                                               cases/   (95% CI)         comments
                                                                                                          deaths

Manufacture of ceramic plumbing fixtures
Thomas &        2055 white men       Exposure to silica and                                                        SMR              Crystalline silica was the




                                                                                                                                                                  IARC MONOGRAPHS VOLUME 93
Stewart         employed >1          talc assessed qualitatively All causes    Total cohort               587      0.9 [0.8–1.0]    major exposure; also
(1987), USA,    yearm 1939–66;       by job title–department     Lung cancer   Total cohort                52      1.4 [1.1–1.9]    exposure to non-fibrous and
5 plants in 1   mortality follow-    by industrial hygienist                    High silica                44      1.8 [1.3–2.4]    fibrous talc
company         up through to                                                   High silica+non-fibrous    21      2.5 [1.6–3.9]
                1 Jan. 1981; vital                                               talc
                status, 96%                                                     High silica+non-fibrous     5      1.7 [0.6–4.0]
                                                                                 talc+fibrous talc
                                                                                High silica+no talc        18      1.4 [0.8–2.2]
Manufacture of pulp and paper
Langseth &      4247 women                                                                                         SIR              Comparison with 5-year
Andersen        employed >1                                     All cancers    Total cohort               380      1.2 (1.1–1.3)    age-specific rates in
(1999),         year, 1920–93;                                  Ovarian                                    37      1.5 (1.1–1.2)    Norwegian women; cancer
Norway, 10      follow-up of                                    cancer                                                              incidence from National
paper mills     cancer incidence,                                Exposure                                  31      1.6 (1.1–2.3)    Cancer Registry
                1953–93                                          ≥3 years
                                                                 Age 25–35                                  6      8.0 (2.9–17.4)
                                                                 years
                                                                Ovarian        Paper mill workers          18      2.1 (1.3–3.4)
                                                                cancer
Table 2.2 (contd)

Reference,     Cohort               Exposure assessment       Organ site   Exposure categories     No. of   Relative risk    Adjustment factors;
location       description                                                                         cases/   (95% CI)         comments
                                                                                                   deaths

Langseth &     Nested case–         Exposure to asbestos, talc Ovarian                                      Odds ratio       Parity, breastfeeding,
Kjaerheim      control study in     and total dust from work cancer        Total dust                       0.8 (0.4–1.7)    tobacco smoking habits,
(2004),        cohort of            histories, questionnaires              Ever talc                        1.1 (0.6–2.2)    family history of breast or
Norway, 10     Langseth &           by industrial hygienists/              Ever asbestos                    2.0 (0.7–5.7)    ovarian cancer; conditional
paper mills    Andersen (1999);     senior employees and                   Asbestos according to            2.2 (0.5–9.1)    logistic regression; odds
               46 cases, 179        international database;                interview                                         ratios unchanged after
               matched controls;    personal use of talc: 76%                                                                adjustment for confounders
               100%                 of cases, 57% of controls;




                                                                                                                                                            TALC
               histologically       personal interviews
               confirmed
Rubber manufacturing industries
Blum et al.    Nested case–         Exposure to polycyclic    Stomach      Company A                                         No information on
(1979), USA,   control study; 100   hydrocarbons,             cancer       High+moderate talc      27       2.4 (1.4–4.1)*   composition or purity of
2 rubber       cases, 4 controls    nitrosamines, carbon                   High talc               13       1.3 (0.9–2.5)*   talc; no increase in risk in
companies      per case; matched    black, talc (high,                                                                       Company B
               on age, race, sex,   moderate, low, none)                                                                     *90% CI
               company; 1964–       from job histories
               73




                                                                                                                                                            335
                                                                                                                                                              336
Table 2.2 (contd)

Reference,      Cohort               Exposure assessment         Organ site      Exposure categories   No. of   Relative risk    Adjustment factors;
location        description                                                                            cases/   (95% CI)         comments
                                                                                                       deaths

Straif et al.   8933 male blue-      Work histories                                                             SMR              SMRs calculated from




                                                                                                                                                              IARC MONOGRAPHS VOLUME 93
(1999),         collar workers       recontructed from cost      Lung cancer                           154      1.2 (1.0–1.4)    national death rates
Germany,        hired after 1 Jan.   centre codes                Stomach                                44      1.2 (0.8–1.6)
5 rubber        1950 and alive                                   cancer
production      1 Jan. 1981;
plants          follow-up, 1 Jan.
                1981 to end of
                1991; cause of
                death known for
                97% of 1521
                deceased
Straif et al.   Same as that of      Same as Straif et al.       Lung cancer     High talc              21      1.9 (1.1–3.1)    Unadjusted; reference: low
(2000),         Straif et al.        (1999) plus semi-                           Medium talc            41      1.1 (0.8–1.6)    exposure to talc
Germany,        (1999)               quantitative cumulative     Stomach         High talc              11      4.3 (2.1–9.0)
5 rubber                             exposure (low, medium,      cancer          Medium talc            12      1.2 (0.6–2.4)
production                           high) to asbestos, talc,    Laryngeal       High talc               3      5.4 (1.1–27.0)
plants                               nitrosamines, carbon        cancer          Medium talc             2      2.8 (0.5–16.7)
                                     black for 95% of cohort
CI, confidence interval; SIR, standardized incidence ratio; SMR, standardized mortality ratio
                                         TALC                                         337

the USA that manufactured ceramic plumbing fixtures. Crystalline silica was said to be
the major occupational exposure of these workers, but, in some parts of the plant,
exposure to fibrous [tremolitic] and non-fibrous [tremolite-free] talc had also occurred.
Vital status was ascertained for 96% of the cohort through to 1 January 1981 and
observed numbers of deaths were compared with numbers expected from cause-specific
mortality rates for white men in the USA. For each job title–department combination,
exposure to silica and talc were qualitatively assessed by an experienced industrial
hygienist. Silica exposure was categorized as none, low or high; high exposure to silica
was further categorized on the basis of no exposure to talc, exposure to fibrous talc and
exposure to non-fibrous talc. The SMR for all causes combined was 0.9 (578 observed
[95% CI, 0.8–1.0]) and that for lung cancer was 1.4 (52 observed [95% CI, 1.1–1.9]). The
excess mortality from lung cancer was seen exclusively among workers who had been
exposed to high levels of silica dust (44 observed; SMR, 1.8 [95% CI, 1.3–2.4]) and, to a
greater extent, in the subgroup with additional exposure to non-fibrous talc (21 observed;
SMR, 2.5 [95% CI, 1.6–3.9]) than in subgroups with additional exposure to fibrous talc
(five observed; SMR, 1.7 [95% CI, 0.6–4.0]) or no exposure to talc (18 observed; SMR,
1.4 [95% CI, 0.8–2.2]). [The Working Group noted that all jobs that involved exposure to
talc also involved high exposure to respirable silica.]

         (b)    Manufacture of pulp and paper
    Langseth and Andersen (1999) examined cancer incidence among a cohort of
4247 women who had been employed for at least 1 year between 1920 and 1993 in the
Norwegian pulp and paper industry. The women had worked mainly in paper sorting and
packing departments in 10 paper mills or in administration (85% of the cohort).
Production was judged to involve occupational exposures that included paper dusts,
microbes, formaldehyde, talc and asbestos (the latter was used as insulation material in
boilers and in the breaks of various rolling machines), but no measurement data were
available. Women were followed for cancer incidence between 1953 and 1993 and SIRs
were calculated by comparing the observed incidence to the 5-year age-specific incidence
rates for the female population of Norway. Information on cancer incidence was obtained
by linkage with the National Cancer Registry and information on dates of death and
emigration was obtained from the Central Bureau of Statistics of Norway. Records of
women who died between 1953 and 1960 were identified manually. Between 1953 and
1993, 535 women in the cohort had died, 65 women had emigrated and 380 new cases of
cancer had been diagnosed. The SIR for all cancers was 1.2 (380 observed; 95% CI, 1.1–
1.3). An excess of ovarian cancer diagnoses was observed (37 observed; SIR, 1.5; 95%
CI, 1.1–2.1). In the analyses, workers were also stratified by exposure into the following
categories: short-term (< 3 years) versus long-term (≥ 3 years); period of first exposure
(1920–39, 1940–59, 1960–74, 1975–93); and time since first exposure (3–14 years, 15–
29 years, ≥ 30 years). The excess risk was predominantly seen among women who had
been employed in the industry for 3 years or more (31 observed; SIR, 1.6; 95% CI, 1.1–
2.3). The excess risk for ovarian cancer was also highest for women under the age of
338                        IARC MONOGRAPHS VOLUME 93

55 years at diagnosis, with an SIR of 8.0 (six observed; 95% CI, 2.9–17.4) for women
aged 25–35 years at diagnosis. Among women who worked in the paper mills, the SIR for
ovarian cancer was 2.1 (18 observed; 95% CI, 1.3–3.4). In the discussion, the authors
noted that talc is added as a filler in paper mills and may contribute to the excess risk for
ovarian cancer observed.
     On the basis of an extended follow-up of cohort members for cancer incidence to the
end of 1999, Langseth and Kjaerheim (2004) conducted a nested case–control study that
included 46 employees who had ovarian cancer and 179 controls individually matched to
cases by incidence density sampling. An experienced oncologist reviewed the pathology
for all cases. Work histories were obtained from personnel records at each mill. Exposure
to asbestos, talc and total dust was assessed on the basis of the work histories,
questionnaires on production processes completed by industrial hygienists and senior
employees, as well as semiquantitative exposure assessments for the 10 mills extracted
from an international database of exposure in the pulp and paper industry. Information on
possible confounders (including use of talc on sanitary napkins, underwear or diapers)
was obtained for 76% of cases and 57% of controls through a personal interview with the
study subject or next of kin. Odds ratios for ovarian cancer were derived by conditional
logistic regression. Ever exposure to asbestos was associated with a non-significantly
increased odds ratio for ovarian cancer of 2.0 (95% CI, 0.7–5.7), while ever exposure to
talc (odds ratio, 1.1; 95% CI, 0.6–2.2) or to total dust (odds ratio, 0.8; 95% CI, 0.4–1.7)
was associated with risks that were close to unity. Among women who were interviewed,
the odds ratio for exposure to asbestos was 2.2 (95% CI, 0.5–9.1). This estimate was
unchanged after adjustment for multiple potential confounders, including parity,
breastfeeding, tobacco smoking habits and family history of breast or ovarian cancer. The
odds ratios for occupational exposure to talc and total dust were similarly unchanged after
adjustment for confounding.

         (c)    Rubber manufacturing industries
    Following the finding of an excess risk for stomach cancer in a cohort of rubber
workers in the USA, Blum et al. (1979) carried out a nested case–control study of
stomach cancer. Cases were defined as deaths from stomach cancer in two of the rubber
companies from 1 January 1964 to 31 December 1973 (100 deaths in total). Four controls
were matched to each case on age, race, sex and company. Using the recorded job history
of each worker, the investigators and a group of environmental scientists assessed the
potential for exposure (high, moderate, low or none) in each job to the following
substances: polycyclic hydrocarbons, nitrosamines, carbon black and detackifiers (anti-
sticking agents which were mainly talc). No information was available on the purity or
composition of the talc (i.e. whether it contained asbestiform materials or other fibrous or
non-fibrous carcinogens). While no clear elevation of odds ratio was reported in
Company B, a significantly increased relative risk of 2.4 (27 observed; 90% CI, 1.4–4.1)
was found in Company A when workers with moderate and high exposure to talc were
                                           TALC                                          339

pooled into one group. High exposure in the latter company was associated with a modest
increase in relative risk of 1.3 (13 observed; 90% CI, 0.7–2.5).
     Based on the employment files of five rubber production plants in Germany, Straif et
al. (1999) conducted a mortality cohort study of 8933 male blue-collar workers who were
hired after 1 January 1950 and who were alive on 1 January 1981. Follow-up was started
on the date of completion of 1 year of employment or 1 January 1981, whichever came
last, and ended on at death, at 85 years of age, at the date of loss to follow-up or
31 December 1991, whichever came first. Cause of death was obtained for 97% of
1521 deceased workers. Work histories were reconstructed from cost centre codes and
were classified into six work areas. SMRs were calculated from national death rates and
were estimated at 1.2 (154 observed; 95% CI, 1.0–1.4) for lung cancer and
1.2 (44 observed; 95% CI, 0.8–1.6) for stomach cancer. In a subsequent analysis (Straif et
al., 2000), information on work history was combined with semiquantitative levels of
exposure to asbestos, talc, nitrosamines and carbon black that were estimated by industrial
hygienists to yield overall estimates of cumulative exposure (low, medium, high) for
approximately 95% of the cohort. Talc is widely used in rubber production and, according
to the authors, asbestos was used in all five plants at least until the early 1980s. In risk
analyses that were unadjusted for exposure to asbestos or other potential workplace
confounders, high and medium occupational exposure to talc were associated with
relative risks for lung cancer of 1.9 (21 observed; 95% CI, 1.1–3.1) and 1.1 (41 observed;
95% CI, 0.8–1.6), respectively, when workers with low exposure were used as the
reference group. Equivalent risk estimates were 4.3 (11 observed; 95% CI, 2.1–9.0) and
1.2 (12 observed; 95% CI, 0.6–2.4) for stomach cancer and 5.4 (three observed; 95% CI,
1.1–27.0) and 2.8 (two observed; 95% CI, 0.5–16.7) for laryngeal cancer. Separate risk
analyses with adjustment for potential confounders were not performed. [The Working
Group noted that risk analyses that adjusted for estimates of exposure to asbestos were not
presented.]

2.1.3    Community-based studies
    Chen et al. (1992) conducted a case–control study in Beijing, China, of several risk
factors for ovarian cancer that included occupational exposure to talc. A total of 220 cases
of newly diagnosed epithelial ovarian cancer were identified between 1984 and 1986
through the Beijing Cancer Registry. Of these, 67 [30.5%] were excluded due to death,
37 [16.8%] due to unavailability of current contact information and four [1.8%] due to
patient refusal. The analysis was carried out on 112 cases and 224 community controls,
with two age-matched controls per case. Potential controls were excluded if they had a
history of serious illness, although the percentage of those excluded for this reason was
not specified. In addition, 15 of the 224 eligible controls initially selected [6.7%] refused
to participate in the study and were therefore replaced by other eligible controls. No
information was provided on the age range of the cases and controls, although the mean
age at the time of interview was similar for cases (48.5 years) and controls (49.0 years).
340                        IARC MONOGRAPHS VOLUME 93

All cases were confirmed by laparotomy and pathological review. Data were collected in-
person by trained interviewers. Odds ratios were estimated using conditional logistic
regression adjusted for education and parity. Occupational exposure to talc was associated
with an odds ratio for ovarian cancer of 0.9 (95% CI, 0.3–2.9). [The Working Group
noted the incomplete ascertainment of cases of ovarian cancer due to the nature of the
cancer-reporting system in China, the large number of cases who were excluded due to
death and the exclusion of controls who had a history of serious health problems, which
may have resulted in selection bias.]
     Hartge and Stewart (1994) analysed the occupational histories of 296 women aged
20–79 years who were diagnosed with ovarian cancer between 1978 and 1981 in the
Washington DC area of the USA and 343 hospital-based controls matched to cases on age
and race. Pathology was confirmed for all cases. Trained interviewers used a standardized
questionnaire to obtain information from each participant on their lifetime job history and
occupational exposure to talc. An industrial hygienist blinded to the case status of each
participant evaluated each industry and occupation for potential exposure to talc, ionizing
radiation, polycyclic aromatic hydrocarbons and solvents, using a scale of 0 (definitely
not exposed) to 4 (definitely exposed). Women were considered to be exposed if they had
an exposure rating of 2–4 (possibly, probably or definitely exposed). Logistic regression
adjusted for race, age, parity, gynaecological surgery and duration of employment in jobs
with the exposure of interest was used for the analyses. Controlling for additional known
and potential risk factors for ovarian cancer, including parity, oral contraceptive use and
cigarette smoking, did not change these estimates. Women who were classified as having
been occupationally exposed to talc had odds ratios below the null, although the
confidence limits were wide due to the small number of exposed women (12 cases,
31 controls). For women with 10 or more years of employment in an occupation with
possible, probable or definite exposure to talc, the odds ratio was 0.5 (five exposed cases;
95% CI, 0.2–1.5). The risk for ovarian cancer was not significantly elevated for any
exposure or duration of employment assessed. [Limitations of this analysis include the
small number of women occupationally exposed to talc.]
     ‘Industrial talc’ was one of the substances evaluated by the exposure assessment team
in the community-based case–control study carried out in Montréal, Canada (Siemiatycki,
1991) and described in detail in the monograph on carbon black. About 5% of the
4263 study subjects was considered to be exposed to industrial talc, mostly in the
following occupations: painters, motor vehicle mechanics and farmers. Exposure to talc
was analysed in relation to 11 different types of cancer, at two levels of exposure (any or
substantial). No statistically significant increases in risk were observed. The odds ratios
for lung cancer were 0.9 (35 exposed cases; 90% CI, 0.6–1.4) for ‘any exposure’ and
0.9 (nine exposed cases; 90% CI, 0.5–1.9) for ‘substantial exposure’. Prostate cancer was
the only site with a borderline significant increased risk, with an odds ratio of
1.4 (29 exposed cases; 90% CI, 1.0–2.1) for ‘any exposure’ and 1.1 (seven exposed cases;
90% CI, 0.5–2.3) for ‘substantial exposure’. [The main limitation of the study was the
reliance on expert opinions of exposure rather than measurements for exposure
                                          TALC                                         341

assessment. Also, exposure levels tend to be lower in such community-based studies than
in the workplaces that are selected for cohort studies. The main advantages were the
availability of histologically confirmed incident cases and detailed information on tobacco
smoking habits and other characteristics of the subjects.]

2.2      Cosmetic use of talc

    This evaluation was limited to ovarian cancer because the Working Group was
unaware of studies of other cancers associated with the cosmetic use of talc.
    The content of body powders used by women varies by product and has changed over
time, although data that document this are limited. Before the mid-1970s, body powders
may have contained varying but usually small quantities of amphiboles. After that time,
amphibole was voluntarily reduced to less than detectable levels, at least in western
Europe and the USA. Other non-talc minerals that include chlorite, quartz, carbonates and
pyrophyllite may also be found in body powders in varying and occasionally not
insignificant quantities in the past and currently. Other added ingredients, which depend
on the product, could include cornstarch and perfumes.

2.2.1    Cohort studies
     Gertig et al. (2000) carried out the only prospective cohort analysis that reported an
association between perineal use of talcum, baby or deodorant powder and the risk for
ovarian cancer. This analysis was conducted among participants in the Nurses’ Health
Study, a cohort of 121 700 female registered nurses who had been followed since 1976.
All participants were between the ages of 30 and 55 years and lived in one of 11 states of
the USA at study enrolment. Questionnaires were mailed to participants every 2 years
beginning in 1976 to obtain information on the medical history of each woman and
potential risk factors for cancer, heart disease and other conditions. The 1982
questionnaire requested information on history and frequency of application of powder to
the perineal area (none, daily, one to six times a week, less than once a week) and history
of application of powder to sanitary napkins (no/yes). ‘Ever talc use’ was classified as
ever use on either the perineal area or on sanitary napkins. The study population included
78 630 women who responded to the questions on powder use in 1982 and who were not
excluded from the analysis for another reason (cancer other than non-melanoma skin
cancer before 1982, bilateral oophorectomy, surgery with unknown number of ovaries
removed or radiation therapy) and entailed 984 212 person–years of follow-up. Between
1982 and June 1996, 307 incident cases of epithelial ovarian cancer were identified by
self-reporting in a biennial questionnaire, by deaths that were reported by relatives or
postal authorities or through the National Death Index. Physicians blinded with respect to
exposure status reviewed pathology reports to confirm each case and to determine the
histological subtype for each tumour as reported by the woman’s pathologist. Pooled
logistic regression was used to model the incidence rate ratio of ovarian cancer for the
342                         IARC MONOGRAPHS VOLUME 93

exposed versus unexposed participants. The reported results were adjusted for age in
years, parity (defined as the number of pregnancies lasting 6 months or more), duration of
oral contraceptive use, body mass index, history of tubal ligation, tobacco smoking status
and postmenopausal use of hormones. Additional covariates considered as potential
confounders included age at menarche, duration of breastfeeding and age at menopause.
Family history of ovarian cancer was not considered to be a confounder, since
information on this covariate was not collected until 1992. In 1982, 40.4% of the cohort
reported a history of perineal talc use (n = 31 789) and 14.5% reported a history of daily
use (n = 11 411). Overall, no association between ‘ever use’ of talcum powder and total
risk for epithelial ovarian cancer (relative risk, 1.1; 95% CI, 0.9–1.4) and no trend of
increased risk for ovarian cancer with increasing frequency of talc use were observed.
However, a modest increase in risk for serous invasive cancers was associated with any
history of talc use (relative risk, 1.4; 95% CI, 1.0–1.9) and a borderline significant trend
was found with increasing frequency of use (p for trend = 0.05). Among women without a
history of tubal ligation, no association was observed between history of talc use and total
risk for epithelial ovarian cancer (relative risk, 1.0; 95% CI, 0.7–1.3). Similarly, history of
tubal ligation did not modify the association between the use of talc and risk for serous
invasive cancers. [Limitations of this analysis include the availability of exposure
information at a single time-point only, the relatively short follow-up period after
exposure assessment and the lack of information on age at first use of talc, duration of use
of talc, current use of talc in 1982 and use of talc before tubal ligation or pregnancy, all of
which are potentially important parameters based on previous studies.]

2.2.2    Case–control studies (Table 2.3)
    Cramer et al. (1982) reported the first epidemiological study of genital talc use and
the risk for ovarian cancer. The analysis included 215 cases of epithelial ovarian cancer
and 215 population-based controls matched to cases by age (within 2 years), race and
residence. All cases were Caucasian, English-speaking residents of Massachusetts, USA,
aged 18–80 years, who had been diagnosed with epithelial ovarian cancer between
November 1978 and September 1981. Cases were identified through pathology logs or
tumour boards of 12 participating Boston hospitals. Among 297 eligible cases identified
during the time period of interest, 41 were excluded from the study due to: physician
refusal (13), patient refusal (14) or death/change of address (14). An additional 41 cases
were excluded because they had a non-ovarian primary (18) or a non-epithelial ovarian
tumour based on a review of pathology specimens by the authors. Controls were
identified though annual listings of the names, addresses and ages of all Massachusetts
residents. Among 475 women identified as potential controls, 11.8% (56) could not be
reached, 6.1% (29) were ineligible due to previous bilateral oophorectomy, 4.2% (20)
were the wrong age, not Caucasian or did not speak English and 32.6% (155) refused to
participate. All cases and controls were interviewed in person to obtain information on
their medical history, menstrual and reproductive histories, as well as potential for exposure
Table 2.3. Case–control studies of epithelial ovarian cancer (invasive or borderline) and cosmetic use of talc

Reference,        Characteristics of cases Exposure assessment                Exposure       No. of  Odds ratio       Adjustment for       Comments
study location,   and controls                                                categories     exposed (95% CI)         potential
study period                                                                                 cases                    confounders

Cramer et al.     215 Caucasian,             In-person interviews;            ‘Any’ perineal 92      1.6 (1.0–2.5)    Parity,              Distribution of tumour
(1982)            English-speaking           information collected on         exposure to                             menopausal           histologies similar for
Boston, MA,       women, aged 18–80          medical history, menstrual       talc                                    status, religion,    exposed and unexposed
USA, 1978–81      years; identified          and reproductive history,        As dusting     32      3.3 (1.7–6.4)    marital status,      cases; potential for talc
                  through pathology logs     potential or definite exposure   powder on                               educational level,   exposure by way of
                  or tumour boards of 12     to talc                          perineum and                            weight, age at       contraceptives, pelvic
                  Boston hospitals;                                           sanitary                                menarche, exact      surgery or perineal hygiene
                  histological                                                napkins                                 parity, oral         considered; no information
                  confirmation of                                                                                     contraceptive use,   on duration or frequency of
                  diagnosis;                                                                                          postmenopausal       talc use; low participation
                  215 population-based                                                                                use of hormones,     rates among controls (56%




                                                                                                                                                                          TALC
                  controls identified                                                                                 tobacco smoking      of cases matched with no
                  through annual listings                                                                                                  refusals; 27% matched after
                  of names, ages and                                                                                                       1 refusal; 17% matched after
                  addresses of all                                                                                                         2 or more refusals)
                  Massachusetts
                  residents; matched by
                  age (±2 years), race,
                  residence
Hartge et al.     135 incident cases         Interviews to collect            ‘Any’ use of   67      0.7 (0.4–1.1)    Age, race,           Questions on talc added
(1983)            treated at participating   information on reproductive      talc                                    pregnancy            after study began; no
Washington        hospitals;                 and sexual history, medical      ‘Genital’       7      2.5 (0.7–10.0)                        information on duration or
DC, USA,          171 population-based       history, drug use and other      exposure to                                                  frequency of exposure; no
1974–77           controls; frequency-       exposures, exposure to talc      talc                                                         controlling for other
                  matched by age, race,      categorized as ‘any’ or                                                                       potential confounders;
                  hospital                   ‘genital’ (includes use on                                                                    potential for selection bias
                                             genitals, on sanitary napkins
                                             or on underwear)




                                                                                                                                                                          343
                                                                                                                                                                        344
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment              Exposure          No. of Odds ratio       Adjustment for     Comments
study location,   and controls                                              categories        exposed (95% CI)        potential
study period                                                                                  cases                   confounders

Whittemore et     188 incident cases        Structured in-person            Type of                                                     No trend of increasing risk
al. (1988),       diagnosed at              interviews; information         application                                                 with increasing duration of
San Francisco,    8 hospitals, aged 18–74   collected on medical history,   Perineum only      22     1.5 (0.8–2.6)   Parity, oral      exposure, as measured in




                                                                                                                                                                        IARC MONOGRAPHS VOLUME 93
CA, USA 1983–     years; histological       menstrual and reproductive      Sanitary pads       5     0.6 (0.2–1.8)   contraceptive use years of talcum powder use
85                verification of           history, family history,        only                                                        on the perineum prior to
                  diagnosis;                environmental exposures         Diaphragm only      9     1.5 (0.6–3.6)                     tubal ligation or
                  539 controls selected     (talc, coffee, alcohol,         Any two            67     1.4 (0.9–2.0)                     hysterectomy;
                  from women                tobacco); talc exposure         All three           1     0.4 (0.0–2.9)                     non-statistically significant
                  hospitalized for non-     categorized by type of                                                                      trend of increasing risk
                  cancerous conditions      application, duration of use    Duration of use                           Parity            with increasing frequency
                  (n=280) or from the       prior to tubal ligation or      (years)                                                     of exposure, as measured in
                  population using          hysterectomy, frequency of      None              103     1.0                               number of applications of
                  random digit-dialling     use                             1–9                34     1.6 (1.0–2.6)                     talc to the perineum per
                  (n=259); matched by                                       ≥10                50     1.1 (0.7–1.7)                     month
                  age (±5 years), race,                                                                               Parity
                  hospital/date of                                          Frequency of use
                  admission (hospital                                       Never            97       1.0
                  controls) or telephone                                    1–20             41       1.3 (0.8–2.0)
                  area code/prefix                                          times/month
                  (population controls)                                     ≥20 times/month 44        1.5 (0.9–2.2)
                                                                            30 times/month –          1.3 (0.9–1.9)
                                                                            p for trend               0.19
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment                Exposure            No. of Odds ratio        Adjustment for     Comments
study location,   and controls                                                categories          exposed (95% CI)         potential
study period                                                                                      cases                    confounders

Booth et al.      235 incident cases        Interviewer- administered         Frequency of use                             Age,               Participation rates not
(1989),           from 15 hospitals, aged   standard questionnaire;           Never            76         1.0              socioeconomic      provided; questions on talc
London and        65 years or under at      information obtained on           Rarely            6         0.9 (0.3–2.4)    status             use added 3 months after
Oxford, United    diagnosis; diagnosed      reproductive and menstrual        Monthly           7         0.7 (0.3–1.8)                       start of study; data on talc
Kingdom,          within 2 years of         history, on exposure to           Weekly           57         2.0 (1.3–3.4)                       exposure missing for 18
1978–83           interview; histological   exogenous estrogens,              Daily            71         1.3 (0.8–1.9)                       cases and 17 controls
                  confirmation of           cigarettes, talc; talc exposure   p for trend                 0.05
                  diagnosis;                categorized by frequency of
                  451 hospital-based        use on perineum and whether
                  controls selected from    it was used to store a
                  same 15 hospitals;        diaphragm




                                                                                                                                                                             TALC
                  same age distribution
                  as the cases
Harlow &          116 Caucasian women       In-person interviews;             ‘Any’ perineal      49      1.1 (0.7–2.1)    Age, parity, use   Cases diagnosed with
Weiss (1989),     from 3 urban counties     information obtained on           use                                          of oral            borderline (serous or
western           captured in Seattle-      reproductive, sexual and                                                       contraceptives     mucinous) tumours; study
Washington        Puget Sound Cancer        medical histories, as well as     Type of powder                                                  limited by incomplete
State, USA,       Surveillance System,      perineal exposure to talc; talc   used                                                            information on powder use
1980–85           aged 20–79 years;         exposure categorized as ‘any’     Cornstarch only      4      0.8 (0.2–3.8)                       and small size;
                  independent               perineal use, by method of        Baby powder         18      0.8 (0.4–1.9)                       no significant association
                  pathological review:      use, and by type of powder        only                                                            between method of powder
                  73% of total;             used.                             Baby powder,        22      0.9 (0.5–2.0)                       use and risk for borderline
                  histological agreement:                                     combined                                                        tumours
                  94% of reviewed cases;                                      Talc, unspecified   13      1.0 (0.4–2.4)
                  158 white population-                                       Deodorizing         10      3.5 (1.2–28.7)
                  based controls selected                                     powder only
                  by random-digit                                             Deodorizing,        14      2.8 (1.1–11.7)
                  dialling; matched by                                        combined
                  age, county of
                  residence




                                                                                                                                                                             345
                                                                                                                                                             346
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment           Exposure          No. of Odds ratio      Adjustment for    Comments
study location,   and controls                                           categories        exposed (95% CI)       potential
study period                                                                               cases                  confounders

Chen et al.       112 women from            Interviewer-administered        Use on perineum 7      3.9 (0.9–10.6) Education, parity Age range of cases and
(1992),           Beijing Cancer            questionnaire; information      or lower                                                controls not reported




                                                                                                                                                             IARC MONOGRAPHS VOLUME 93
Beijing, China,   Registry, with a mean     obtained on menstrual,          abdomen
1984–86           age of 48.5 years;        obstetric, marital, medical,
                  confirmation of           family and dietary histories as
                  diagnosis by              well as exposure to talc
                  laparotomy and            (perineally and
                  pathological              occupationally); perineal
                  examination in all        exposure reported as yes/no
                  cases;
                  224 population-based
                  controls selected first
                  on basis of area of
                  residence of cases and
                  then randomly from
                  census lists of all
                  women within 1 year
                  of age of identified
                  case; matched by age;
                  mean age, 49.0 years
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment               Exposure           No. of Odds ratio       Adjustment for      Comments
study location,   and controls                                               categories         exposed (95% CI)        potential
study period                                                                                    cases                   confounders

Harlow et al.     235 white women from      In-person interviews;            ‘Any’ perineal     114     1.5 (1.0–2.1)   Parity,             Odds ratio for women with
(1992),           10 hospitals in           information collected on         use of talc                                education,          >10 000 lifetime
Boston, MA,       metropolitan Boston       occupational history, medical    Method of                                  marital status,     applications unchanged
Massachusetts,    area, aged 18–76 years;   and reproductive history,        application                                religion, use of    after excluding applications
USA, 1984–87      independent               dietary history, tobacco         Sanitary napkins     9     1.1 (0.4–2.8)   sanitary napkins,   that occurred after tubal
                  pathological              smoking, hygienic practices      or underwear                               douching, age,      ligation or hysterectomy
                  confirmation of           including perineal exposure to   only                                       weight              (odds ratio, 1.7; 95% CI,
                  diagnosis;                talc; exposure to talc           Partner or          20     1.2 (0.6–2.4)                       1.0–3.0); significant
                  239 population-based      categorized by type of           applications to                                                increase in odds ratio for
                  controls randomly         application, brand of            diaphragm                                                      women with >10 000
                  selected from town        powders, duration and            Dusting on         85      1.7 (1.1–2.7)                       lifetime applications
                  registers; matched by     frequency of use                 perineum                                                       observed after excluding




                                                                                                                                                                           TALC
                  age (±2 years), race,                                      Frequency (no.                                                 use of talc during non-
                  precinct of residence;                                     per month)                                                     ovulatory periods and after
                  no history of bilateral                                    None               121     1.0                                 surgical sterilization (odds
                  oopherectomy                                               <5                  32     1.5 (0.8–2.7)                       ratio, 2.8; 95% CI, 1.4–5.4)
                                                                             5–29                24     1.2 (0.6–2.2)
                                                                             ≥30                 58     1.8 (1.1–3.0)
                                                                             p for trend                0.046
                                                                             Years of use
                                                                             None               121     1.0
                                                                             <10                 14     1.2 (0.5–2.6)
                                                                             10–29               49     1.6 (1.0–2.7)
                                                                             ≥30                 51     1.6 (1.0–2.7)
                                                                             p for trend                0.07
                                                                             Total
                                                                             applications
                                                                             None               121     1.0
                                                                             <1000               18     1.3 (0.7–2.7)
                                                                             1000–10 000         54     1.5 (0.9–2.4)
                                                                             >10 000             42     1.8 (1.0–3.0)
                                                                             p for trend                0.09




                                                                                                                                                                           347
                                                                                                                                                                            348
Table 2.3 (contd)

Reference,          Characteristics of cases Exposure assessment                Exposure            No. of Odds ratio       Adjustment for    Comments
study location,     and controls                                                categories          exposed (95% CI)        potential
study period                                                                                        cases                   confounders

Rosenblatt et al.   77 women admitted to       Questionnaire administered       Genital fibre use   67      1.0 (0.2–4.0)   Parity           Investigators encountered




                                                                                                                                                                            IARC MONOGRAPHS VOLUME 93
(1992),             Johns Hopkins              by telephone and in the          Method of                                                    difficulty finding controls
Baltimore, MD,      Hospital as in-patients    hospital; information            application                                                  who met all of the
USA, 1981–85        for treatment or           collected on genital and         Diaphragm use       14      3.0 (0.8–10.8) Parity, education matching criteria. For
                    diagnosis; diagnosed       respiratory exposure to fibre-   with powder                                No adjustment     analysis, 46 matched sets,
                    within 6 months of         containing substances, such      Genital bath talc   22      1.7 (0.7–3.9) Highest weight, of which 31 sets had 2
                    admission; residents of    as talc; sources of genital      Sanitary napkin     21      4.8 (1.3–17.8) 1 year prior to   cases and 1 control;
                    the USA; pathological      exposure included                with talc                                  diagnosis         limitations include small
                    confirmation of            contraceptive methods            exposure                                                     study size, broad definition
                    diagnosis;                 (diaphragm, condoms),                                                                         of fibre exposure, limited
                    46 hospital-based          dusting of perineum and                                                                       information available on
                    controls selected from     sanitary products; sources of                                                                 perineal exposure to talc
                    female in-patients with    respiratory exposure
                    no gynaecological or       included: use of face and/or
                    malignant conditions;      body powders; residential or
                    matched a posteriori       occupational exposure to
                    by age (±5 years), race,   fibre-containing substances,
                    closest date of            such as talc, asbestos,
                    diagnostic admission       fiberglass; estimation of
                                               ‘dose’ by adding number of
                                               years of exposure from all
                                               sources
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment                Exposure           No. of Odds ratio       Adjustment for    Comments
study location,   and controls                                                categories         exposed (95% CI)        potential
study period                                                                                     cases                   confounders

Tzonou et al.     189 women                 Questionnaire administered in     Talc application                           Age, education, Study limited by very low
(1993),           hospitalized for          hospital by medical residents;    in perineum                                weight, age at    prevalence of perineal talc
Athens, Greece,   ovarian cancer surgery    information collected on          No                 183     1.0             menarche,         use
1989–91           in 2 major cancer         medical and reproductive          Yes                  6     1.1 (0.3–4.0)   menopausal
                  hospitals in Greater      histories, as well as personal,                                              status, age at
                  Athens, aged 75 years     demographic and                                                              menopause,
                  or under; histological    socioeconomic variables;                                                     parity, age at
                  confirmation of           qualitative assessment of talc                                               first birth,
                  diagnosis;                exposure (yes/no use in the                                                  smoking status,




                                                                                                                                                                         TALC
                  200 hospital visitor      perineal region)                                                             alcohol use,
                  controls (selected from                                                                                coffee
                  visitors to patients                                                                                   consumption,
                  hospitalized in the                                                                                    use of
                  same wards as cases);                                                                                  analgesics, use
                  not matched to cases                                                                                   of tranquilizers
                  by age                                                                                                 or hypnotics, use
                                                                                                                         of hair dyes




                                                                                                                                                                         349
                                                                                                                                                                              350
Table 2.3 (contd)

Reference,         Characteristics of cases Exposure assessment                 Exposure          No. of Odds ratio       Adjustment for      Comments
study location,    and controls                                                 categories        exposed (95% CI)        potential
study period                                                                                      cases                   confounders

Purdie et al.      824 incident cases          Interviewer-administered         Use of talc       [467]   1.3 (1.0–1.5)   Parity; other
(1995),            diagnosed and               standardized questionnaire in    around the        56.7%                   potential
Queensland,        registered in all major     clinic (cases) or home (some     abdomen or                                confounders, e.g.
New South          gynaecological-             cases, all controls);            perineum                                  contraceptive
Wales, Victoria,   oncology treatment          information collected on                                                   use, also




                                                                                                                                                                              IARC MONOGRAPHS VOLUME 93
Australia, 1990–   centres in 3 states, aged   medical, reproductive, family                                              considered
93                 18–79 years;                and occupational histories, as
                   independent                 well as dietary factors and
                   pathological                history of talc use
                   confirmation of
                   diagnosis;
                   860 population-based
                   controls selected
                   randomly from
                   electoral rolls,
                   stratified by age and
                   geographical region
Shushan et al.     200 incident cases (164     Interviewer-administered          Use of talc                              No control for      Study limited by the very
(1996),            invasive, 36                standard questionnaire;           Moderate/a lot   21      [1.97]          confounding         sparse information on talc
Israel, 1990–93    borderline) diagnosed       information collected on                                   (p = 0.04)                          use and the unavailability
                   and reported to Israel      reproductive history, use of                                                                   of adjusted results for the
                   Cancer Registry, aged       oral contraceptives and                                                                        association between use of
                   36–64 years;                fertility drugs, exposure to                                                                   talc and the risk for ovarian
                   histological                talc; exposure to talc stratified                                                              cancer
                   confirmation of             into ‘never/seldom’,
                   diagnosis;                  ‘moderate/a lot’
                   408 population-based
                   controls selected by
                   random-digit dialing;
                   matched by
                   geographical area
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment             Exposure         No. of Odds ratio       Adjustment for      Comments
study location,   and controls                                             categories       exposed (95% CI)        potential
study period                                                                                cases                   confounders

Chang & Risch     450 incident cases       Interviewer-administered        ‘Any’ exposure 198       1.4 (1.1–1.9)   Age at interview,   Authors do not specify
(1997),           (primary, invasive and   questionnaire; information      to talc                                  duration of oral    whether cases were
metropolitan      borderline); aged 35–    collected on menstrual and      Type of exposure                         contraceptive       identified through a cancer
Toronto and       79 years; histological   reproductive history, use of    Sanitary napkins   51    1.3 (0.9–2.0)   use, parity         registry or some other
southern          confirmation of          hormones and oral               After bathing    172     1.3 (1.0–1.7)   (number of full-    reporting mechanism.
Ontario,          diagnosis;               contraceptives, and use of      Frequency of                             term                Borderline significant trend
Canada, 1989–     564 population-based     talc; exposure to talc          after-bath use                           pregnancies),       observed with increasing
92                controls identified      categorized on basis of ‘any’   (times/month)                            duration of         duration of exposure to
                  through provincial       exposure, type of exposure,     None                     1.0             lactation per       talc, but not with increasing




                                                                                                                                                                        TALC
                  records of all           frequency and duration of       <10                76    1.8 (1.2–2.7)   pregnancy,          frequency of exposure
                  homeowners, tenants      perineal application            10–25              54    1.1 (0.7–1.7)   history of tubal
                  and family members;                                      >25                41    1.0 (0.6–1.5)   ligation or
                  randomly selected                                        Per 10                   0.9 (0.7–1.1)   hysterectomy,
                  from same residential                                    applications per                         family history of
                  area; matched by age                                     month                                    breast or ovarian
                  within 15-year age                                       Duration of                              cancer
                  groups                                                   after-bath use
                                                                           (years)
                                                                           None                     1.0
                                                                           <30               60     1.7 (1.1–2.6)
                                                                           30–40              71    1.4 (1.0–2.2)
                                                                           >40                41    0.9 (0.5–1.4)
                                                                           Per 10 years of          1.1 (1.0–1.2)
                                                                           use




                                                                                                                                                                        351
                                                                                                                                                   352
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment              Exposure         No. of Odds ratio       Adjustment for     Comments
study location,   and controls                                              categories       exposed (95% CI)        potential
study period                                                                                 cases                   confounders

Cook et al.       313 incident cases (234   Structured in-person            Lifetime perineal                        Adjusted for age
(1997)            invasive,                 interviews; information         application
Western           79 borderline)            collected on medical and        None              154    1.0




                                                                                                                                                   IARC MONOGRAPHS VOLUME 93
Washington        identified from records   reproductive histories,         Any               159    1.5 (1.1–2.0)   Adjusted for age
State, USA,       of Cancer Surveillance    smoking habits, birth control   Exclusive use of
1986–1988         System of western         methods and use of genital      powder for
                  Washington; white         powders and deodorant           Perineal dusting   55    1.8 (1.2–2.9)
                  residents of three        sprays; exposure to genital     Diaphragm          22    0.8 (0.4–1.4)
                  counties (King, Pierce,   powders assessed on the basis   storage
                  Snohomish), aged 20–      of ‘any’ lifetime exposure,     Dusting sanitary   12    1.5 (0.6–3.6)
                  79 years; no              method of use and cumulative    napkins                                  Adjusted for age
                  information on whether    lifetime exposure (days,        Deodorant spray    18    1.5 (0.8–3.0)   and other
                  diagnosis was             months or lifetime              Any use of                               methods of
                  histologically            applications)                   powder for                               genital powder
                  confirmed;                                                Perineal dusting   95    1.6 (1.1–2.3)   application
                  422 white population-                                     Diaphragm          46    1.0 (0.6–1.6)
                  based controls selected                                   storage
                  by random digit-                                          Dusting sanitary   38    0.9 (0.5–1.5)
                  dialling (part of a                                       napkins                                  Adjusted for age
                  larger control pool for                                   Deodorant spray    40    1.9 (1.1–3.1)   and other
                  several studies of                                        Cumulative                               methods of
                  cancer in women);                                         lifetime perineal                        genital powder
                  matched by age                                            dusting (days)                           application
                                                                            None              154    1.0
                                                                            ≤2000              20    1.8 (0.9–3.5)
                                                                            2001–5000          24    1.6 (0.9–2.9)
                                                                            5001–10 000        21    1.2 (0.6–2.4)
                                                                            >10 000            28    1.8 (0.9–3.4)
Table 2.3 (contd)

Reference,         Characteristics of cases Exposure assessment         Exposure          No. of Odds ratio   Adjustment for   Comments
study location,    and controls                                         categories        exposed (95% CI)    potential
study period                                                                              cases               confounders

Eltabbakh et al.   ‘Study’ group: 50       Self-administered, 44-item   Perineal use of   224     p=0.003     No control for   ‘Cases for this study were
(1998),            women admitted for      questionnaire completed at   talc              (48.1%)             confounding      women diagnosed with
Buffalo, NY,       treatment of primary    hospital admission                                                                  primary peritoneal cancers.
USA, 1982–96       extra-ovarian                                                                                               Case definition excluded
                   peritoneal cancer to                                                                                        patients with diagnoses of
                   Roswell Park Cancer                                                                                         peritoneal mesothelioma,
                   Institute; histological                                                                                     borderline tumours of
                   confirmation of                                                                                             peritoneum or invasive




                                                                                                                                                              TALC
                   diagnosis;                                                                                                  ovarian cancer; no healthy
                   ‘control’ group: 466                                                                                        controls enrolled in this
                   women treated for                                                                                           study. ‘Controls’ were
                   primary ovarian cancer                                                                                      women diagnosed with
                   at same centre;                                                                                             primary epithelial ovarian
                   pathological review of                                                                                      cancer. Control definition
                   diagnosis                                                                                                   excluded patients with
                                                                                                                               diagnoses of non-epithelial
                                                                                                                               ovarian cancer and ovarian
                                                                                                                               cancer secondary to
                                                                                                                               metastases from other sites.




                                                                                                                                                              353
                                                                                                                                                      354
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment              Exposure          No. of Odds ratio        Adjustment for      Comments
study location,   and controls                                              categories        exposed (95% CI)         potential
study period                                                                                  cases                    confounders




                                                                                                                                                      IARC MONOGRAPHS VOLUME 93
Godard et al.     170 incident cases with   Standardized 57-item            ‘Ever’ use of talc [18]    2.5 (0.9–6.6)   Age at
(1998),           primary invasive or       questionnaire; telephone or     on perineum        (10.6%)                 menarche, age at
Montreal,         borderline epithelial     in-person interviews                                                       menopause,
Quebec,           tumours, identified at    conducted with cases, no                                                   parity, age at
Canada, 1995–     two gynaecological        information on how controls                                                first and last
96                clinics, aged 20–84       were interviewed; qualitative                                              childbirth,
                  years; histological       assessment of perineal talc                                                duration of oral
                  confirmation of           exposure (ever/never)                                                      contraceptive
                  diagnosis;                                                                                           use, age at last
                  170 population-based                                                                                 oral
                  controls selected by a                                                                               contraceptive
                  modified random-digit                                                                                use, tubal
                  dialling method;                                                                                     ligation, alcohol
                  frequency-matched by                                                                                 use, previous
                  age (±1 year), French                                                                                breast or
                  Canadian ethnicity                                                                                   abdominal
                                                                                                                       surgery
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment                Exposure           No. of Odds ratio       Adjustment for       Comments
study location,   and controls                                                categories         exposed (95% CI)        potential
study period                                                                                     cases                   confounders

Cramer et al.     563 incident cases         In-person interviews using       No genital         411     1.0             Age, study site,
(1999),           (including borderline      standardized questionnaire;      exposure                                   parity, oral
eastern           tumours) identified        information collected on         Any genital        152     1.6 (1.2–2.1)   contraceptive
Massachusetts     through hospital           medical and reproductive         exposure                                   use, body mass
and New           tumour boards or           histories, family history and    Method of use                              index, family
Hampshire,        statewide cancer           personal habits; multiple        No use             312     1.0             history of breast
USA, 1992–97      registries; age range      questions on potential routes    Non-genital         99     1.1 (0.8–1.5)   or ovarian
                  not provided;              of talc exposure (non-genital,   areas                                      cancer, history of
                  histological               genital, husband’s use),         Dusting             71     1.5 (1.0–2.2)   tubal ligation
                  confirmation of            brands used, age at first use,   perineum




                                                                                                                                                         TALC
                  diagnosis for all cases;   duration and frequency of use    Dusting sanitary    20     1.5 (0.7–3.1)
                  523 population-based                                        napkins
                  controls selected by                                        Dusting              8     1.2 (0.4–3.6)
                  random-digit dialling                                       underwear
                  and through annual                                          More than one       53     2.2 (1.3–3.6)
                  listings of names, ages                                     method
                  and addresses of all                                        Frequency
                  Massachusetts                                               (uses/month)
                  residents (women over                                       None               312     1.0
                  the age of 60 years);                                       <30                 64     2.2 (1.4–3.6)
                  frequency-matched by                                        30–39               59     1.7 (0.8–1.8)
                  age (±4 years), location                                    ≥40                 23     1.7 (0.8–3.1)
                  of residence                                                Duration of use
                                                                              (years)
                                                                              None               312     1.0
                                                                              <20                 55     1.9 (1.2–3.0)
                                                                              20–30               32     1.3 (0.8–2.3)
                                                                              >30                 59     1.4 (0.9–2.3)




                                                                                                                                                         355
                                                                                                                                                      356
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment   Exposure       No. of Odds ratio       Adjustment for   Comments
study location,   and controls                                   categories     exposed (95% CI)        potential
study period                                                                    cases                   confounders




                                                                                                                                                      IARC MONOGRAPHS VOLUME 93
Cramer et al.                                                    Total no. of
(1999) (contd)                                                   applications
                                                                 None           312     1.0
                                                                 <3000           51     1.8 (1.1–3.0)
                                                                 3000–10 000     36     1.4 (0.8–2.4)
                                                                 >10 000         59     1.4 (0.9–2.2)
                                                                 p for trend            0.16
                                                                 Total no. of                                            Censored analysis excludes
                                                                 applications                                            talc applications that
                                                                 (censored                                               occurred during non-
                                                                 analysis)                                               ovulatory years or after
                                                                 None           312     1.0                              hysterectomy or tubal
                                                                 <3000           59     1.5 (1.0–2.4)                    ligation. Includes non-
                                                                 3000–10 000     51     1.7 (1.1–2.8)                    genitally exposed women.
                                                                 >10 000         36     1.8 (1.0–3.2)
                                                                 p for trend            0.02
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment             Exposure           No. of Odds ratio       Adjustment for      Comments
study location,   and controls                                             categories         exposed (95% CI)        potential
study period                                                                                  cases                   confounders

Wong et al.       462 incident cases       Self-administered, 44-item      Method of use                              Age, parity, oral   Case population largely
(1999)            admitted for treatment   questionnaire completed at      Never              241     1.0             contraceptive       that reported by Eltabbakh
Buffalo, NY,      of primary extra-        hospital admission;             Sanitary napkin     13     0.9 (0.4–2.0)   use, smoking,       et al. (1998); 32 cases,
USA, 1982–92      ovarian peritoneal       information collected on        Genital or thigh   157     1.0 (0.8–1.3)   family history of   39 controls did not recall
                  cancer to Roswell Park   medical, social, family,        area                                       ovarian cancer,     duration of use.
                  Cancer Institute, mean   dietary and occupational        Both                51     1.1 (0.7–1.7)   age at menarche,
                  age, 54.9 years;         histories; method of talc use   Duration of use                            menopausal
                  histological             (never, sanitary napkin,        (years)                                    status, income,




                                                                                                                                                                       TALC
                  confirmation of          genital/thigh area, both)       None               241     1.0             education,
                  diagnosis;               assessed and duration of use    1–9                 39     0.9 (0.6–1.5)   geographical
                  693 hospital-based                                       10–19               49     1.4 (0.9–2.2)   location, history
                  controls treated for                                     ≥20                101     0.9 (0.6–1.2)   of tubal ligation
                  non-gynaecological                                                                                  or hysterectomy
                  malignancies at same
                  cancer centre; mean
                  age, 54.9 years;
                  frequency-matched to
                  cases by age at
                  diagnosis (±5 years)




                                                                                                                                                                       357
                                                                                                                                                                          358
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment               Exposure          No. of Odds ratio       Adjustment for       Comments
study location,   and controls                                               categories        exposed (95% CI)        potential
study period                                                                                   cases                   confounders

Ness et al.       767 incident cases        Standardized in-person           Method of use                             Age, parity, race,   Risk for ovarian cancer




                                                                                                                                                                          IARC MONOGRAPHS VOLUME 93
(2000),           identified at 39          interviews; information          Never             349     1.0             family history of    compared with 50 women
eastern           hospitals in the          collected on sexual activity,    Feet, arms,       335     1.4 (1.1–1.6)   ovarian cancers,     with primary peritoneal
Pennsylvania,     Delaware Valley           use of contraceptives,           breasts                                   oral                 cancers; no control for
southern New      region; aged 20–69;       menstrual and reproductive       Genital/rectal    161     1.5 (1.2–2.0)   contraceptive        confounding; analysis of
Jersey,           diagnosis within 6        history, and history and         Sanitary napkin    77     1.6 (1.1–2.3)   use, tubal           duration examined risk for
Delaware, USA,    months prior to           duration of talc use (genital,   Underwear          70     1.7 (1.2–2.4)   ligation,            cases reporting use of talc
1994–1998         interview; pathological   non-genital applications,        Diaphragm/         10     0.6 (0.3–1.2)   hysterectomy,        on the feet, genital and
                  review of a random        exposure via male sexual         cervical cap                              lactation            rectal areas.
                  subset of cases (n =      partners)                        Male partner       56     1.0 (0.7–1.4)
                  120)                                                       Duration of use
                  1367 population-based                                      (years)
                  controls identified                                        Never             401     1.0
                  through random digit                                       <1                 17     2.0 (1.0–4.0)
                  dialing (≤65 years of                                      1–4                76     1.6 (1.1–2.3)
                  age) and Health Care                                       5–9                40     1.2 (0.8–1.9)
                  Financing                                                  ≥10               233     1.2 (1.0–1.5)
                  Administration lists
                  (65–69 years of age);
                  frequency matched by
                  age and location of
                  residence
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment            Exposure           No. of Odds ratio       Adjustment for     Comments
study location,   and controls                                            categories         exposed (95% CI)        potential
study period                                                                                 cases                   confounders

Langseth &        35 (invasive and          In-person interviews           ‘Ever’ use of talc 12     1.2 (0.4–3.2)   Adjusted for       Nested case–control study
Kjaerheim         borderline tumours)       conducted at mills or by       for personal                              possible           conducted in a cohort study
(2004),           selected from cohort of   telephone; information         hygiene                                   confounders, but   of 10 pulp and paper mills;
Norway, 1953–     4247 female pulp and      collected on occupational                                                not explicitly     many missing values
99                paper workers; cohort     history, household exposure                                              stated             among proxy respondents
                  follow-up, 1953–99;       to asbestos, menstrual and
                  histological review and   reproductive history,




                                                                                                                                                                      TALC
                  confirmation of           hereditary risk of cancer, as
                  diagnosis;                well as talc use on sanitary
                  121 selected from the     napkins, underwear or diapers
                  cohort by incidence       or by husband in genital area.
                  density sampling;
                  matched by birth (year
                  ±2 years); controls had
                  no ovarian cancer and
                  had intact ovaries




                                                                                                                                                                      359
                                                                                                                                                                       360
Table 2.3 (contd)

Reference,        Characteristics of cases Exposure assessment              Exposure           No. of Odds ratio       Adjustment for      Comments
study location,   and controls                                              categories         exposed (95% CI)        potential
study period                                                                                   cases                   confounders

Mills et al.      249 incident cases        Telephone interview to obtain   Perineal use of                            Age,                Cumulative use calculated
(2004),           from 22 counties          information on medical          talc                                       race/ethnicity,     as frequency (categorical
central           diagnosed in two          history, menstrual and          Never              143     1.0             duration of oral    weighting from 0–3)
California,       regional cancer           reproductive history, family    Ever               106     1.4 (1.0–1.9)   contraceptive       multiplied by duration.




                                                                                                                                                                       IARC MONOGRAPHS VOLUME 93
USA, 2000–01      registries, using rapid   history of cancer, history of   Frequency of use                           use,
                  case ascertainment        perineal talc exposure          Never              143     1.0             breastfeeding.
                  procedures;               (frequency, duration and        <1/week             34     1.3 (0.9–2.1)   Additional
                  histological              calendar years of use);         1–3/week            31     1.6 (0.7–1.8)   covariates
                  confirmation of           ‘cumulative’ use calculated     4–7/week            41     1.7 (1.1–2.6)   considered to be
                  diagnosis for a subset    by multiplying frequency        p for trend                0.015           potential
                  of cases;                 (categorical variable) by       Duration of use                            confounders
                  1105 population-based     duration in months              (years)                                    included family
                  controls identified by                                    Never              143     1.0             history of breast
                  random-digit dialling;                                    ≤3                  18     1.0 (0.6–1.8)   or ovarian
                  frequency-matched by                                      4–12                32     1.9 (1.2–3.0)   cancer, parity,
                  age, race, ethnicity                                      13–30               29     1.5 (0.9–2.3)   history of
                                                                            >30                 21     1.2 (0.7–2.1)   pregnancy, body
                                                                            p for trend                0.045           mass index,
                                                                            Cumulative use                             hysterectomy,
                                                                            Never              143     1.0             tubal ligation,
                                                                            1st quartile        18     1.0 (0.6–1.8)   duration of post-
                                                                            (lowest)                                   menopausal use
                                                                            2nd quartile        28     1.8 (1.1–3.0)   of hormones.
                                                                            3rd quartile        34     1.7 (1.1–2.7)
                                                                            4th quartile        20     1.1 (0.6–1.8)
                                                                            (highest)
                                                                            p for trend                0.051

CI, confidence interval
                                           TALC                                          361

to talc by way of contraceptives, perineal hygiene or surgery. Ninety-two cases (42.8%)
and 61 controls (28.4%) reported a history of regular use of talc as a dusting powder to
the perineum, on sanitary napkins or on both. After adjustment for parity (yes/no) and
menopausal status (pre-/post-), a significant association was found between ‘any perineal
use’ of talcum powder and the risk for ovarian cancer (odds ratio, 1.9; 95% CI, 1.3–2.9).
This association was attenuated but still significant after adjustment for additional
potential confounders, including religion, marital status, level of education, weight, age at
menarche, parity (number of children), oral contraceptive use, menopausal use of
hormones and tobacco smoking (adjusted odds ratio, 1.6; 95% CI, 1.0–2.5). A single type
of perineal exposure to talc (either as a dusting powder to the perineum or on sanitary
napkins) was associated with a borderline significantly increased risk for ovarian cancer
(odds ratio, 1.6; 95% CI, 1.0–2.5) after adjustment for parity and menopausal status, while
a history of both types of perineal exposure was associated with a significant increase in
risk (adjusted odds ratio, 3.3; 95% CI, 1.7–6.4). No association was seen between other
potential sources of exposure to talc (pelvic surgery, use of condoms, use of diaphragm or
using talc for diaphragm storage) and the risk for ovarian cancer. In addition, the results
were essentially unchanged after excluding women who had had a tubal ligation or
hysterectomy (odds ratio, 2.8; P < 0.003), although the authors noted that these surgical
procedures are usually performed at mid-life when substantial exposure to talc may
already have occurred. The distribution of tumour histologies was similar for exposed and
unexposed cases; 53.7% of tumours were classified as serous among the unexposed cases
and 48.9% among the exposed cases with ‘any’ perineal use of talc. [Limitations of this
report include the lack of information on duration and frequency of talc use. In addition,
participation rates among the controls were quite low (50%), although the authors noted
in a secondary analysis that, when cases were matched to the first control selected (i.e.
100% participation), a positive association was also found (odds ratio, 2.44; P < 0.05).]
     Hartge et al. (1983) published a brief report of a study conducted between 1974 and
1977 in the Washington DC (USA) area. The study included 197 cases treated for
pathologically confirmed epithelial ovarian cancer at participating hospitals and
197 controls treated at the same hospitals for conditions other than pregnancy,
malignancies and gynaecological or psychiatric diseases. Controls were frequency-
matched to cases by age, race and hospital. Interviews were conducted in the hospital for
controls and at home for most cases to collect information on reproductive and sexual
history, medical history, drug use and other exposures. Questions on exposure to talc were
added after the study began. As a result, the analysis included only 135 cases and
171 controls with information on exposure to talc. Sixty-seven cases [49.6%] and 100
controls [58.5%] reported ‘any’ use of talc (including non-genital uses), while seven cases
[5.2%] and three controls [1.8%] reported genital use of talc (including use on genitals, on
sanitary napkins or on underwear). No association was observed between ‘any’ use of talc
and the risk for ovarian cancer (odds ratio, 0.7; 95% CI, 0.4–1.1). This estimate was
unchanged after adjustment for race, age and pregnancy. A non-significant positive
association was found between genital use of talc and the risk for ovarian cancer (odds
362                        IARC MONOGRAPHS VOLUME 93

ratio, 2.5; 95% CI, 0.7–10.0). [Limitations of this study included its small size and the low
prevalence of genital use of talc, the lack of information on its duration and frequency and
age at first use, the lack of control for other potential confounders and the increased
potential for selection bias due to different interviewing protocols for cases and controls.
In addition, no information was given in this brief report on the methods used in the
analysis to control for confounding.]
     Whittemore et al. (1988) analysed the association between perineal use of talc and the
risk for invasive epithelial ovarian cancer among 188 cases and 539 controls in the San
Francisco Bay area (CA, USA). Cases were residents of northern California, aged 18–
74 years, who had been diagnosed with an invasive ovarian tumour between January
1983 and December 1985 at one of eight hospitals. Controls were either selected from
among women who had been hospitalized for a non-cancerous condition at one of these
eight hospitals or were identified from the population using random-digit dialling.
Women in each control group were matched to each case by age (within 5 years) and race
(white, black, other), plus hospital and date of admission (within 3 months) for the
hospital controls (n = 280) and telephone area code and prefix for the population-based
controls (n = 259). Structured interviews were conducted in the homes of participants to
obtain information on the history, frequency and duration of perineal use of talc, medical
history and additional covariates of interest (menstrual and reproductive histories, family
history and environmental exposures, such as consumption of alcohol, coffee and
tobacco). Of 317 eligible cases, eight (2.5%) were excluded due to physician refusal,
30 (9.5%) due to patient refusal, 44 (13.9%) due to death or incapacitating illness and
47 (14.8%) due to non-invasive tumours, which left 188 (59.3%) for inclusion in the
analysis. Among the controls, 68% of the women identified as eligible hospital controls
(n = 354) and 71% of the women identified by telephone as eligible population-based
controls (n = 329) agreed to participate. After excluding controls matched to cases with
bordeline tumours, 280 hospital controls and 259 population controls were included in the
analysis (Wu et al., 1988). Exposure to talc was categorized by type of application
(perineum only, sanitary pads only, diaphragm only, any two types of application or all
three types of application), duration of use before tubal ligation (none, 1–9 years,
≥ 10 years, unknown) and frequency of use (none, 1–20 applications per month,
> 20 applications per month, unknown). Conditional logistic regression was used to
calculate the odds ratio for each exposure and to test for trend. Ninety-seven cases
(51.6%) and 247 controls (45.8%) reported previous use of talcum powder on the
perineum to yield an odds ratio of 1.40 (P = 0.06) after adjustment for parity. Since the
odds ratios were similar when hospital-based and population-based controls were
analysed separately, analyses using the combined group of controls were reported. After
adjustment for parity and oral contraceptive use, the odds ratio for use of talc on the
perineum only was 1.5 (95% CI, 0.8–2.6). No significant associations were observed with
either individual or multiple types of perineal talc use, including the combination of use
on the perineum, sanitary napkins and a diaphragm (odds ratio, 1.4; 95% CI, 0.9–2.0 for
any two types of use versus 0.4; 95% CI, 0.0–2.9 for all three types combined). No
                                           TALC                                           363

significant trend was observed with duration of talc use on the perineum before tubal
ligation or hysterectomy. Odds ratios were 1.6 (95% CI, 1.0–2.6) for 1–9 years of
exposure and 1.1 (95% CI, 0.7–1.7) for more than 10 years of exposure. A non-significant
trend of increased risk with increasing frequency of perineal use of talc was observed,
with an overall odds ratio of 1.3 (95% CI, 0.9–1.9; P = 0.19) for 30 applications per
month. When stratified by history of perineal use of talc (yes/no) and history of tubal
ligation or hysterectomy (yes/no), women who had used talc perineally and but had not
undergone surgery for sterilization had the highest risk for ovarian cancer (odds ratio, 1.3;
95% CI, 0.9–2.0). [Limitations of this study included the lack of information on talc use.]
     Booth et al. (1989) reported results of a hospital-based case–control study of the risk
for ovarian cancer conducted in 15 hospitals in London and Oxford (United Kingdom)
from October 1978 to February 1983. Women aged 65 years or under at diagnosis and
who were diagnosed within 2 years of the study interview were eligible for inclusion. A
total of 280 potential cases were identified, interviewed and classified with respect to
tumour histology. After excluding 45 women, 235 cases were included in the analysis. A
total of 451 controls with the same age distribution as the cases were selected from the
same 15 hospitals. Controls had a range of admission diagnoses; gastrointestinal disease
(n = 105) and bone or joint disease (n = 70) were the most common. Women were
excluded as controls if they had a history of bilateral oophorectomy or if they had a
condition related to oral contraceptive use or other reproductive factors. Participation rates
were not provided. Interviewers used a standard questionnaire to obtain information on
reproductive and menstrual history, as well as exposure to exogenous estrogens, cigarettes
and talc. Talc exposure was categorized according to the frequency of perineal use (never,
rarely, monthly, weekly or daily) and whether it was used for storage of a diaphragm.
Multiple logistic regression adjusted for age and socioeconomic status was conducted.
Fifty-seven cases [24.3%] and 77 controls [17.1%] reported a history of weekly use of
talc in the genital area, while 71 cases [30.2%] and 139 controls [30.8%] reported daily
use. Weekly genital use of talc was associated with a significantly increased risk for
ovarian cancer (odds ratio, 2.0; 95% CI, 1.3–3.4), while daily use was associated with a
non-significant increase in risk (odds ratio, 1.3; 95% CI, 0.8–1.9), after adjustment for age
and socioeconomic status. The p-value for trend with increasing frequency of use was of
borderline significance (P = 0.05). The percentage of diaphragm users who reported
storing their diaphragm in talc was not significantly different between the cases (86%)
and controls (81%). [Limitations of this hospital-based study included the limited
information on talc use. As participation rates were not provided, the possibility of
selection bias is difficult to evaluate. Although covariates such as oral contraceptive use
or parity were available, it was not explicitly stated if they were evaluated.]
     Harlow and Weiss (1989) conducted a study of perineal use of powder and the risk
for borderline ovarian cancer in western Washington State, USA. Cases were
116 Caucasian women aged 20–79 years who had been diagnosed with borderline serous
or mucinous epithelial ovarian cancer between 1980 and 1985, and who were identified
by International Classification of Diseases-0 codes obtained from a population-based
364                        IARC MONOGRAPHS VOLUME 93

cancer-reporting system. Controls were identified from the same counties of residence by
random-digit dialling. A total of 158 women with a similar age distribution to the cases
and who had not undergone a bilateral oophorectomy were included in the analysis. Cases
and controls were interviewed in-person to obtain information on reproductive, sexual
and medical histories, as well as on perineal exposure to talc (through multiple open-
ended questions about the history of powder use of the participant). Among all eligible
cases and controls identified for the study, 68% of the cases and 74% of the controls were
interviewed. The authors controlled for age (20–39, 40–59 or 60–79 years), parity
(nulliparous or parous) and oral contraceptive use (ever/never). Exposure to talc was
broadly categorized as ‘any perineal use of dusting powders’ (after bathing, on sanitary
napkins or for diaphragm storage) and further subcategorized according to method of use
(diaphragm storage only, after bathing only, sanitary napkins only, after bathing and on
sanitary napkins and specific combinations of the various methods) and type of powder
used (cornstarch only, baby powder only, talc unspecified (no combined use), deodorizing
powder only or combinations of powders). Forty-nine cases [42.2%] and 64 controls
[40.5%] reported a history of ‘any perineal exposure to powder’ to yield an odds ratio of
1.1 (95% CI, 0.7–2.1). When analysed by the type of powder used, the risk for borderline
ovarian cancer was elevated only for perineal use of deodorizing powder alone (odds
ratio, 3.5; 95% CI, 1.2–28.7) or in combination with other powders (odds ratio, 2.8;
95% CI, 1.1–11.7). No association was noted for the use of baby powder alone (odds
ratio, 0.8; 95% CI, 0.4–1.9) or for combined use (odds ratio, 0.9; 95% CI, 0.5–2.0) or for
other unspecified use of talc (odds ratio, 1.0; 95% CI, 0.4–2.4). No significant association
was found between risk for borderline tumours and any individual method of powder use,
including use after bathing, on sanitary napkins or for diaphragm storage. The authors
reported no increase in risk with increasing number of days of powder use, although the
data were not provided in the paper. [Limitations of this study included the incomplete
information on powder use and its small size.]
     Chen et al. (1992) (described in detail in Section 2.1.2) conducted a case–control
study in Beijing, China, of several risk factors for epithelial ovarian cancer that included
perineal exposure to talc (yes/no use of dusting powder to the lower abdomen or
perineum for 3 or more months). The analysis was carried out on 112 newly diagnosed
cases identified between 1984 and 1986 through the Beijing Cancer Registry and
224 age-matched community controls (two controls per case). Seven cases [6.3%] and
five controls [2.2%] reported use of talc-containing powders which resulted in an odds
ratio of 3.9 (95% CI, 0.9–10.6) after adjustment for education and parity. [The Working
Group noted the incomplete ascertainment of cases of ovarian cancer due to the nature of
the cancer-reporting system in China, the large number of cases that were excluded due to
death and the exclusion of controls who had a history of serious health problems (which
may have resulted in selection bias), the limited information on perineal use of talc, the
lack of adjustment for other potential confounding variables, the small number of cases
and the low prevalence of talc use.]
                                           TALC                                          365

     Harlow et al. (1992) analysed perineal exposure to talc and the risk for ovarian cancer
among 235 cases and 239 controls in the Boston, MA metropolitan area (USA). Cases
were diagnosed with ovarian cancer between June 1984 and September 1987 at one of
10 Boston hospitals and controls were identified from town registers listing the name, age
and address of all residents in Massachusetts. All cases were Caucasian women aged 18–
76 years at diagnosis and were similar to the controls with respect to race, age and area of
residence. Of 397 cases identified during the study period, 31% were not interviewed due
to physician and/or patient refusal, death or change of address. After excluding women
whose cancer diagnosis was not confirmed by an independent pathology review [9.4% of
eligible cases], 235 women were included in the analysis. A total of 526 women were
contacted as potential controls. Of these, 239 [45.4%] were interviewed, 25% could not
be reached, 10% reported a previous bilateral oophorectomy and 19% did not wish to
participate in the study. In-person interviews were conducted with cases and controls to
obtain information on occupational history, medical and reproductive histories, dietary
history, cigarette smoking and hygienic practices (use of douches, types of sanitary
protection used, perineal exposure to talc). Exposure to talc was categorized on the basis
of ‘any’ exposure, the method of application (dusting on sanitary napkins and/or
underwear, via partner or application to diaphragm, dusting on perineum), the brand used,
age at first use, duration and frequency of use. Total lifetime exposure to talc was
estimated by cumulating the frequency of exposure and years of use to arrive at a
summary measure of the total number of applications (< 1000, 1000–10 000, > 10 000).
Covariates evaluated as potential confounders included age, education, marital status,
religion, weight, use of oral contraceptives and parity; of these, age, education
(< 12 years, > 12 years), marital status (never/ever), religion (Jewish, non-Jewish), weight
(< 140 lb, ≥ 140 lb) and parity (0, 1–2, > 2) were included in all multivariable models. A
history of ‘any’ perineal exposure to talc-containing powders was reported by 48.5% of
cases and 39.3% of controls to yield an odds ratio of 1.5 (95% CI, 1.0–2.1). When the
method of application was examined, only direct application to the perineum as a dusting
powder was associated with a significant increase in risk (odds ratio, 1.7; 95% CI, 1.1–
2.7). Women who reported at least 30 applications of talcum powder per month had a
significant increase in risk (odds ratio, 1.8; 95% CI, 1.1–3.0), while women with fewer
applications per month did not. A significant positive trend was seen with number of
monthly applications (P = 0.046). Women with at least 10 years of perineal exposure had
a borderline significant increase in risk (odds ratio, 1.6; 95% CI, 1.0–2.7) and the p-value
for trend was also of borderline significance (P = 0.07). Analyses stratified by age at first
use indicated that women who first used talc genitally before the age of 20 years had the
highest risk (odds ratio, 1.7; 95% CI, 1.1–2.7); those stratified by years since last use
suggested that women with the most recent perineal use of talc (within the previous
6 months) had the highest risk (odds ratio, 2.3; 95% CI, 1.3–4.0). In an analysis stratified
by use before versus after 1960, women who reported some perineal use of talc before
1960 had a significantly elevated risk for ovarian cancer (odds ratio, 1.7; 95% CI, 1.1–
2.7), while women with exclusive genital use of talc after 1960 did not (odds ratio, 1.1;
366                        IARC MONOGRAPHS VOLUME 93

95% CI, 0.6–2.1). Women who had used more than 10 000 lifetime applications had a
borderline significant increase in risk (odds ratio, 1.8; 95% CI, 1.0–3.0). This was
unchanged after excluding applications that occurred after tubal ligation or hysterectomy
(odds ratio, 1.7; 95% CI, 1.0–3.0). However, when use of talc during non-ovulatory
periods and after surgical sterilization was excluded, the increase in risk associated with
more than 10 000 lifetime applications was significant (odds ratio, 2.8; 95% CI, 1.4–5.4).
In analyses of each histological type and grade, the strongest associations were seen for
endometrioid tumours (odds ratio, 2.8; 95% CI, 1.2–6.4) and tumours of borderline
invasiveness (odds ratio, 2.4; 95% CI, 1.2–4.5) (Table 2.4).
     Rosenblatt et al. (1992) conducted a hospital-based case–control study among
77 women who were hospitalized at Johns Hopkins Hospital in Baltimore, MD (USA) for
ovarian cancer (cases) and 46 who were hospitalized for non-gynaecological, non-
malignant conditions (controls). The cases were newly diagnosed with pathologically
confirmed epithelial ovarian cancer between 1981 and 1985, the majority of whom were
aged 40–69 years. Of 140 eligible cases, 108 (77.1%) were interviewed. Thirteen were
subsequently excluded because no control was identified and 18 were excluded for an
unspecified reason. Controls were matched to cases by age, race and date of diagnostic
admission. Information on genital and respiratory exposure to fibre-containing substances
(talc, asbestos and fibreglass), as well as potential confounders, was collected using a
structured questionnaire which was administered in the hospital and by telephone.
Covariates that were considered to be potential confounders included tobacco use,
‘ovulatory time period’, parity, family history of cancer, obesity, education, education of
husband, previous history of cancer, marital status, religion and the use of oral
contraceptives and other methods of contraception. Sources of genital fibre exposure
(yes/no) included diaphragm use and dusting of either the perineum or sanitary napkins
with talcum powder. Potential sources of respiratory fibre exposure (yes/no) included use
of face or body powders containing talc, insulation installed at residence and living in the
vicinity of or employment in a fibre-emitting industry (such as shipyard, asbestos or talc
mine, asbestos/talc/fibreglass processing plant). A large percentage of both the cases
(87%) and controls (88%) reported exposure to genital fibre, with an odds ratio of 1.0
(95% CI, 0.2–4.0) after adjustment for parity. A long duration of genital fibre use (median
duration, ≥ 37.4 years) was associated with a borderline significant increase in the risk for
ovarian cancer (odds ratio, 2.4; 95% CI, 1.0–5.8) after adjustment for religion. Odds ratios
were also calculated for genital use of bath talc (odds ratio, 1.7; 95% CI, 0.7–3.9), use of
talc on sanitary napkins (odds ratio, 4.8; 95% CI, 1.3–17.8) and use of talc on a
diaphragm (odds ratio, 3.0; 95% CI, 0.8–10.8). No association was observed between risk
for ovarian cancer and history of previous gynaecological or abdominal surgery that may
have resulted in peritoneal exposure to talc. [Limitations of this study included the very
small number of cases and controls, the broad definition of fibre exposure used in certain
exposure variables and the limited information on perineal exposure to talc.]
     Tzonou et al. (1993) conducted a hospital-based case–control study of risk factors for
epithelial ovarian cancer in the Greater Athens region of Greece. The cases were 189 women
Table 2.4. Perineal talc use and ovarian cancer risk: by tumour histology

References                 No. of        Histology                 Relative riska (95% CI)
                           cases

Harlow et al. (1992)        60           Serousb                   1.4 (0.9–2.2)
                            17           Mucinous                  1.2 (0.6–2.5)
                            18           Endometrioid              2.8 (1.2–6.4)
Chang & Risch (1997)       254           Serousb                   1.3 (1.0–1.9)
                            80           Mucinous                  1.6 (1.0–2.6)
                            74           Endometrioid              1.7 (1.0–2.8)
Cook et al. (1997)         131           Serous                    1.7 (1.1–2.5)
                            43           Mucinous                  0.7 (0.4–1.4)
                            36           Endometrioid              1.2 (0.6–2.3)




                                                                                             TALC
Cramer et al. (1999)       229           Serous invasive           1.7 (1.2–2.4)
                            83           Mucinous                  0.8 (0.4–1.4)
                           130           Endometrioid/clear cell   1.0 (0.7–1.6)
Wong et al. (1999)         136           Serous                    1.2 (0.7–2.1)
                            11           Mucinous                  1.5 (0.6–4.0)
                            21           Endometrioid              1.4 (0.7–2.7)
Gertig et al. (2000)        76           Serous invasive           1.4 (1.0–1.9)
Mills et al. (2004)         42           Serous invasive           1.8 (1.1–2.8)
                            10           Mucinous invasive         2.6 (0.9–7.4)
                            14           Endometrioid              1.3 (0.6–2.6)

CI, confidence interval
a
  Any or ever use of talc
b
  Includes borderline and invasive serous tumours




                                                                                             367
368                        IARC MONOGRAPHS VOLUME 93

under 75 years of age who underwent surgery for ovarian cancer at one of two cancer
hospitals in Athens between June 1989 and March 1991. The controls were 200 women
under 75 years of age who were residents of Greater Athens and who visited patients
hospitalized in the same wards as the cases during the study period. Ninety per cent of the
eligible cases and 94% of the eligible controls agreed to participate. In-hospital interviews
were conducted to collect information on a range of demographic, socioeconomic and
reproductive factors, as well as information on exposure to hair dyes, analgesics,
tranquilizers and talc. Exposure to talc was assessed qualitatively as ‘yes/no’ application
of talc in the perineal region. In multivariable analyses, models were adjusted for age in
5-year groups, education, weight, age at menarche, menopausal status, age at menopause,
parity, age at first birth, tobacco smoking status, alcohol use, coffee consumption and the
other exposures of interest (use of analgesics, tranquilizers and hair dyes). Application of
talc to the perineal region was reported by six cases [3.2%] and seven controls [3.5%] to
yield an odds ratio of 1.1 (95% CI, 0.3–4.0) after adjustment for the potential
confounders. [Limitations of this hospital-based case–control study included the very low
prevalence of perineal use of talc.]
     Purdie et al. (1995) conducted a case–control study among women in the three most
populous Australian states—Queensland, New South Wales and Victoria. Cases were
women, aged 18–79 years, who had been diagnosed with epithelial ovarian cancer
between August 1990 and December 1993 at gynaecological oncology treatment centres
in one of these three regions. Women were excluded if they had a metastatic tumour, were
outside the eligible age range, could not be contacted, were too ill or were incapable of
completing the questionnaire in conjunction with a trained interviewer (because of
language difficulties or psychiatric conditions). Each case was confirmed by an
independent pathological review of tissue specimens. Of 1116 cases identified during the
study period, 201 (18%) were ineligible (e.g. due to a non-ovarian primary cancer or age
at diagnosis). Among the 915 eligible cases, 824 (90%) agreed to participate and were
interviewed. Reasons for non-participation included death before interview (50 cases),
patient refusal (34 cases) and physician refusal (seven cases). Controls were identified
from the electoral roll and were similar to the cases in age distribution and area of
residence. Women were excluded as a control if they had a history of ovarian cancer or
bilateral oophorectomy, could not be reached or could not complete the questionnaire.
Among 1527 potential controls identified from the electoral roll, 1178 were located and
found to be eligible (77%). Of these, 860 agreed to participate in the study (73% of the
eligible controls). Reasons for ineligibility among the controls included failure to locate
the individual (192), inability to complete the questionnaire due to language difficulties, a
psychiatric condition, illness or death (105), previous bilateral oophorectomy (48) and age
(four). Trained interviewers used a standardized questionnaire to collect information on
medical, reproductive, family and occupational histories, as well as data on dietary factors
and history of talc use. Questionnaires were administered face-to-face either in the clinic
(for cases) or in the home of participant (for some cases and all controls). Covariates
evaluated as potential confounders included parity, hysterectomy, tubal ligation, duration
                                            TALC                                           369

of oral contraceptive use, age, education, body mass index, tobacco smoking status,
family history of cancer and multiple menstrual and reproductive factors. Talc use around
the abdomen or perineum was reported by 56.7% of cases and 52% of controls to yield an
odds ratio of 1.3 (95% CI, 1.0–1.5) after adjustment for parity. Although enrolment in the
electoral roll is mandatory in Australia, the authors determined that 28 cases [3.4%] had
never enrolled and the enrolment status could not be confirmed for 46 cases [5.6%]. The
results did not change when the analyses were limited to cases with confirmed enrolment
in the electoral role.
     Green et al. (1997) evaluated the association between tubal ligation or hysterectomy
and the risk for ovarian cancer using the Australian study population described by Purdie
et al. (1995). [The analysis by Green et al. (1997) used the same number of cases but five
fewer controls than Purdie et al. (1995).] Duration of talc use was calculated as age at first
reported use until age at occurrence of the earliest of any of the following events: surgical
sterilization, reported last use of talc, diagnosis or interview. A modest increase in risk for
ovarian cancer was observed with peritoneal use of talc (odds ratio, 1.3; 95% CI, 1.1–1.6).
Neither duration of talc use nor age at first use were associated with risk for ovarian
cancer, although the relative risks (95% CI) were not provided and the duration categories
evaluated were not specified. When compared with women with no history of genital
exposure to talc and patent fallopian tubes, women with a history of talc use and no
history of surgical sterilization had the highest risk for ovarian cancer (odds ratio, 1.3;
95% CI, 1.0–1.7), while women with a history of tubal ligation or hysterectomy and no
talc use had the lowest risk (odds ratio, 0.6; 95% CI, 0.5–0.8). [The primary limitation of
this study was the restricted information on perineal use of talc.]
     Shushan et al. (1996) examined the association between exposure to fertility drugs
and the risk for ovarian cancer among 200 cases of epithelial ovarian cancer (164 invasive
and 36 borderline) and 408 controls. All participants were living in Israel and were 36–
64 years of age at enrolment into the study. Cases were identified through the Israel
Cancer Registry from January 1990 to September 1993. Among 287 women who met the
eligibility criteria (histologically confirmed diagnosis, cancer diagnosed and reported
during study period, born between 1929 and 1957 and alive at time of interview),
87 (30.3%) were excluded because of inability to locate the patient or physician (25%),
illness (1%), refusal by the physician (1%) or refusal by the patient (3%). Controls were
identified by random-digit dialling and were matched to the cases by geographical area.
Women were eligible to be included as a control if they were born in the same period as
the cases. Potential controls were excluded if they had a history of bilateral oophorectomy
(1%). Of 2072 telephone calls that successfully reached a household member,
approximately half of the households [47.8%] contacted had a potentially eligible woman
who was at home. Of these, 16.2% refused to participate and 10.7% were excluded
because the woman did not speak Hebrew. Trained interviewers administered a standard
questionnaire to all cases and controls. The questionnaire collected detailed information
on reproductive history, use of oral contraceptives and fertility drugs, as well as exposure
to talc (never/seldom, moderate/a lot). Although the main association of interest was use
370                        IARC MONOGRAPHS VOLUME 93

of fertility drugs and the risk for ovarian cancer, the authors reported that 21 cases
(10.5%) and 23 controls (5.6%) had a history of moderate or frequent use of talc, which
yielded an unadjusted odds ratio of [1.97] (P = 0.04). [Limitations of this study included
the very sparse information on talc use and the unavailability of adjusted results for the
association between use of talc and the risk for ovarian cancer.]
     Chang and Risch (1997) analysed the association between perineal use of powder and
the risk for ovarian cancer among 450 cases and 564 population controls from
metropolitan Toronto and southern Ontario, Canada. Cases were diagnosed between
November 1989 and October 1992 and were between the ages of 35 and 79 years at entry
into the study. Of 631 cases identified during the study period, 71.3% (450) were
interviewed and included in the analysis. Reasons for non-participation included death
(8.7%), physician refusal (4.6%), severe illness (4.8%), loss to follow-up (2.7%) and
patient refusal (7.9%). Potential controls were identified through records of the Ontario
Ministry of Finance based on their residence and age, were matched to cases within
15-year age groups and were excluded from the study if they had a history of bilateral
oophorectomy more than 1 year before entry into the study. Among 873 eligible controls
identified, 309 [35.4%] did not participate. Reasons included participant refusal (30.2%),
illness (1.9%) or loss to follow-up (3.2%). Interviewers administered a standard
questionnaire during an in-home interview to obtain information on the history, frequency
and duration of use of talcum and cornstarch powder, as well as multiple medical and
reproductive covariates of interest. Talc exposure was categorized on the basis of ‘any’
exposure in the perineal area, on the method of application (directly to the perineum after
bathing or showering, dusting on sanitary napkins), on the frequency of application (< 10,
10–25, > 25 applications per month) and on the duration of exposure (< 30, 30–40,
> 40 years of use). Multiple logistic regression was used in the analyses, with adjustment
for age, duration of oral contraceptive use, parity (defined as the number of full-term
pregnancies), duration of lactation for each pregnancy, history of tubal ligation or
hysterectomy and family history of breast or ovarian cancer. Forty-four per cent of cases
and 36% of controls reported ‘any’ talc use in the perineal area to yield an odds ratio of
1.4 (95% CI, 1.1–1.9). Among the specific types of talc exposure, application to the
perineum after bathing was associated with a borderline significant increase in risk (odds
ratio, 1.3; 95% CI, 1.0–1.7), while application on sanitary napkins (a less common use in
this study population) was associated with an elevated but non-significant increase in risk
(odds ratio, 1.3; 95% CI, 0.9–2.0). A borderline significant trend was seen with increasing
duration of exposure to talc (odds ratio per 10 years of exposure, 1.1; 95% CI, 1.0–1.2),
but not with increasing frequency of exposure. An analysis of duration by category (< 30,
30–40, > 40 years) did not suggest a dose–response relationship (odds ratios of 1.0; 1.7;
95% CI, 1.1–2.6; 1.4; 95% CI, 1.0–2.2 and 0.9; 95% CI, 0.5–1.4, respectively). Use of
cornstarch in the perineal area, either alone or in conjunction with occasional talc, was not
associated with the risk for ovarian cancer, although prevalence of use was low (less than
2% of subjects). To evaluate exposure pre- and post-1970, as well as exposure pre- and
post-tubal ligation or hysterectomy, the authors assumed that participants initiated
                                           TALC                                           371

perineal use of after-bath talc at the age of 20 years. A similar, non-significantly elevated,
risk for ovarian cancer was seen for use pre- and post-1970. A higher odds ratio was seen
for use of after-bath talc before tubal ligation or hysterectomy (odds ratio, 1.1; 95% CI,
1.0–1.2) than for use after these surgical procedures (odds ratio, 1.0; 95% CI, 0.8–1.3).
These estimates did not change when different starting ages, between 15 and 24 years,
were used in the analysis. The authors also evaluated the association between perineal use
of talc and invasive and borderline cancers separately, and found that the risk was
elevated for both tumour types but was significant only for invasive tumours. In addition,
risk was similar across the major histological subtypes of ovarian cancer (serous,
mucinous, endometrioid) (see Table 2.4). [Limitations of this study included the lack of
information on use of talc.]
     Cook et al. (1997) evaluated the association between use of genital powders or
deodorants and the risk for ovarian cancer in a case–control study conducted in three
counties of western Washington State, USA. Cases were aged 20–79 years at diagnosis,
were diagnosed with borderline or invasive epithelial ovarian cancer between 1986 and
1988 and were identified using the population-based Cancer Surveillance System of
western Washington. Controls were identified using random-digit dialling, were residents
of the three counties of interest and were similar in age to the cases. Among 512 eligible
cases identified, 329 were interviewed (64.3%) and 313 were included in the analysis
[61.1%]. A total of 183 eligible cases were not interviewed due to death (104), physician
or patient refusal (73) or loss to follow-up (six). An additional 16 cases who were
interviewed were excluded from the analysis because of non-white race (seven) and
unknown genital use of powder (nine). Among 721 women identified as potential
controls, 521 were interviewed (72.3%) and 422 were included in the analysis [58.5%].
Reasons for excluding interviewed controls from the analysis included: non-white race
(28), age greater than 79 years (five), history of bilateral oophorectomy (58), unknown
oophorectomy status (four) and unknown genital use of powder (four). Information on
powder use, including the type, method, frequency and duration of use, and the covariates
of interest was collected during in-person interviews. Covariates considered to be
potential confounders in multivariable analyses included age, education, income, marital
status, body mass index, oral contraceptive use and parity. A history of ‘any’ lifetime
genital powder use (perineal dusting, diaphragm storage, use on sanitary napkins or use of
deodorant spray) was reported by 50.8% of cases and 39.3% of controls to yield an odds
ratio of 1.5 (95% CI, 1.1–2.0) after adjustment for age. Among the individual methods of
genital use of powder, risk was significantly elevated only for exclusive perineal dusting
(odds ratio, 1.8; 95% CI, 1.2–2.9) after adjustment for age. In analyses adjusted for age
and other types of genital use of powder, both perineal dusting (odds ratio, 1.6; 95% CI,
1.1–2.3) and genital deodorant spray (odds ratio, 1.9; 95% CI, 1.1–3.1) were associated
with risk for ovarian cancer, while use of powder on a diaphragm or on sanitary napkins
was not associated with an increased risk. There was no evidence of an increasing trend in
risk with greater duration of perineal dusting, but a significant positive trend was noted for
both duration (odds ratio, 2.7; 95% CI, 1.1–6.6 for > 12 cumulative lifetime months; p for
372                        IARC MONOGRAPHS VOLUME 93

trend < 0.05) and number of lifetime applications (odds ratio, 2.6; 95% CI, 0.9–7.6 for
> 500 lifetime applications; p for trend < 0.05) of genital deodorant spray. The effect
estimates did not change materially when perineal use of dusting powder after the date of
tubal ligation or hysterectomy was excluded. Risk was significantly elevated among
women with any history of perineal dusting before 1976 (odds ratio, 1.8; 95% CI, 1.1–
2.9), but the authors were unable to evaluate risk for use exclusively after 1976 due to the
small number of women (four cases and 10 controls) who had had this exposure. Among
the individual types of powder evaluated (cornstarch, talcum powder, baby powder,
deodorant powder, scented body/bath powder), risk for ovarian cancer was non-
significantly elevated for ‘any’ use of talcum powder (odds ratio, 1.6; 95% CI, 0.9–2.8)
and bath/body powder use (odds ratio, 1.5; 95% CI, 0.9–2.4) after adjustment for age and
other types of powder use (yes/no). The authors also evaluated the association between
any genital use of powder and the risk for the major histological subtypes of ovarian
cancer (see Table 2.4). Risk was significantly elevated for serous tumours (odds ratio, 1.7;
95% CI, 1.1–2.5) and all other tumour types (odds ratio, 1.8; 95% CI, 1.1–2.8) but not for
mucinous or endometrioid tumours. [Limitations of this study included the relatively low
participation rates among the cases and controls.]
    Eltabbakh et al. (1998) compared risk factors among 50 cases of primary extra-
ovarian peritoneal carcinoma (the ‘study’ group) and 503 cases of primary epithelial
ovarian cancer (the ‘control’ group) treated at Roswell Park Cancer Institute in Buffalo,
NY (USA), between October 1982 and October 1996. No healthy controls were enrolled
in this study. Diagnoses were reviewed by staff in the Division of Pathology (study and
control groups) and were confirmed by a single pathologist as part of another study (study
group only). Information on reproductive history, menstrual history, use of hormones and
contraceptives and personal hygiene was collected through a self-administered, 44-item
questionnaire which all patients were asked to complete during the hospital admission
process. All women who returned a questionnaire were eligible to be included in the
study. Among these patients, the overall questionnaire response rate was 60%. Response
was inversely correlated with severity of disease and response rates were similar for the
two diagnoses included in this study. Because data on perineal talc use was missing for
37 patients in the ‘control’ group, only 466 ovarian cancer patients were included in the
analysis. Women who had primary ovarian cancer were significantly more likely to report
a history of perineal use of talc compared with women who had primary peritoneal cancer
(48.1% versus 26.0%; [crude odds ratio = 2.6] P = 0.003). Among the other
characteristics examined, only age and age at menarche differed significantly in the two
groups. [Limitations of this study included the minimal information on talc use, the low
questionnaire response rate among study participants, particularly among the patients with
more advanced disease, the use of a self-administered questionnaire completed during the
admissions process, which may have limited the quality of the responses, and the lack of a
‘healthy’ comparison group.]
    Godard et al. (1998) evaluated risk factors for familial and sporadic ovarian cancer in
a population of French Canadian women in Montréal, Quebec (Canada). Of 231 cases
                                          TALC                                          373

who were identified between 1995 and 1996 at two gynaecological oncology clinics in
Montréal, 183 (79.2%) were interviewed and 170 (73.6%) were included in the analysis.
Reasons for non-inclusion were death (n = 21), refusal/unavailability to participate
(n = 12), loss to follow-up (n = 15) and tumours were non-epithelial in origin (n = 13). All
cases were between the ages of 20 and 84 years at diagnosis, with a mean age at diagnosis
of 53.7 years and a mean age at interview of 55.9 years. Controls were identified using a
modified random-digit dialling method and were frequency-matched to cases by age
(within 1 year) and French Canadian ethnicity. The mean age at interview for the controls
was 56.7 years. Among 750 households contacted regarding participation in the study,
66.7% (n = 500) either did not have an eligible female resident or did not reply to the
researchers’ inquiries and 10.7% refused to participate. A total of 170 women were
interviewed and included in the analysis as controls. A standardized 57-item questionnaire
was used to obtain information on the family, medical and reproductive history of each
participant. Cases were interviewed either by telephone (30%) or in the study clinics
(70%). No information was given on the methods of interview for control subjects.
Information on family history of cancer was collected to determine whether risk factors
differed for the sporadic and familial cases of ovarian cancer. Familial cases were those
patients who had one or more family members (first, second or third degree relatives)
with breast cancer diagnosed before 55 years of age or ovarian cancer diagnosed at any
age. Sporadic cases were those patients who had no family members with breast cancer
diagnosed before 55 years of age or with ovarian cancer diagnosed at any age. Perineal
exposure to talc was assessed qualitatively (ever/never, with ‘never’ as the baseline).
Covariates that were considered to be potential confounding variables were age at
menarche, age at menopause, parity, age at first and last childbirth, duration of oral
contraceptive use, age at last oral contraceptive use, tubal ligation, alcohol use and
previous breast or abdominal surgery. Talc exposure was more common in cases than
controls, with 10.6% of the cases and 4.7% of the controls reported perineal use of talc
(P = 0.06). No difference between perineal use of talc was reported in the familial and
sporadic cases (P = 0.79). Multivariate analyses were performed comparing all cases, (all,
sporadic, familial) with controls. In these analyses, perineal use of talc was associated
with a non-significant increase in the total risk for ovarian cancer (odds ratio, 2.5; 95%
CI, 0.9–6.6; P = 0.07). Risk was similarly non-significantly elevated for sporadic (odds
ratio, 2.5; 95% CI, 0.9–7.1) and familial cases (odds ratio, 3.3; 95% CI, 0.9–12.4)
compared with the controls. [Limitations of this study included its small size and the lack
of any detailed information on perineal use of talc. The control participation rates may
have been low (although this is not clear) and it is not certain how representative the
controls were.]
     Cramer et al. (1999) analysed the association between genital exposure to talc and the
risk for primary epithelial ovarian cancer among 563 cases and 523 controls residing in
eastern Massachusetts and New Hampshire, USA. Cases were identified between May
1992 and March 1997 through hospital tumour boards or statewide cancer registries.
Among 1080 cases diagnosed in this period (including borderline tumours), 203 (18.8%)
374                         IARC MONOGRAPHS VOLUME 93

were excluded due to death, change of address, inability to speak English, no telephone in
residence or a non-ovarian primary cancer. Of the 877 eligible cases remaining after these
exclusions, 563 (64%) were included in the analysis. The remaining 314 cases were
excluded because of physician refusal (n = 126) and patient refusal (n = 136). Pathology
reports were reviewed to confirm the diagnoses for all cases, and slides were requested
and reviewed in the case of discrepancies between the reported histology and the
histology assigned based on the pathology report review. Controls were identified by
random-digit dialling and town resident books (to identify additional women over the age
of 60 years who lived in Massachusetts) and were frequency-matched to cases by age
(within 4 years) and location of residence. Of the potentially eligible controls, 72% of
those identified by random-digit dialling and 49% of those identified through town books
agreed to participate. All study participants were interviewed in-person using a
standardized questionnaire to obtain information on their medical and reproductive
histories, family history and personal habits. The questionnaire also asked multiple
questions on powder use, including route of exposure (application to non-genital areas,
application to perineum, sanitary napkins or underwear, husband’s use of powders in his
genital area), brand of powder used (talc, cornstarch), age at first use, duration and
frequency of use (< 30, 30–39, > 40 uses per month). Participants were asked about
exposures that occurred at least 1 year before the date of diagnosis (cases) or the date of
interview (controls). The results were adjusted for the following potential confounding
variables: age, state of residence, body mass index, parity, oral contraceptive use, family
history of breast or ovarian cancer and history of tubal ligation. The prevalence of talc use
was higher among cases than controls; 44.6% of cases and 36.1% of controls reported
‘any’ use of talc (included use in both genital and non-genital areas) and 27.0% of cases
and 18.2% of controls reported ‘genital’ use of talc (included dusting of perineum/sanitary
napkins/underwear, either exclusively or in combination). Talc use in non-genital areas
was not associated with risk when compared with women who did not use personal
powder (odds ratio, 1.1; 95% CI, 0.8–1.5). However, genital use of talc was associated
with a significant 60% increase in risk (odds ratio, 1.6; 95% CI, 1.2–2.2). Women who
reported more than one method of talc use in the genital area had an even greater risk for
ovarian cancer (odds ratio, 2.2; 95% CI, 1.3–3.6). No association was observed between
genital use of talc and risk for ovarian cancer among women who had undergone tubal
ligation after adjustment for age (odds ratio, 1.0; 95% CI, 0.5–2.1). Because of the low
prevalence of use (< 1% of the study population) of cornstarch, evaluation of this product
was uninformative. When women who had been exposed to powder only in non-genital
areas were excluded from the analysis, no linear trend was observed between risk for
ovarian cancer and age at first genital use of talc, duration of use, frequency of use or total
number of lifetime applications. However, when non-genitally exposed women were
included in the analysis, a significant linear trend was observed with increasing number of
lifetime applications, after talc applications that occurred during non-ovulatory years or
after tubal ligation or hysterectomy were excluded (P = 0.02). Additional findings of
interest included: a non-significant increase in risk among married women with no
                                          TALC                                         375

personal talc use whose husbands had used talc for genital hygiene (odds ratio, 1.5; 95%
CI, 0.9–2.5); and a stronger association between genital use of talc and risk for ovarian
cancer among women who had used talc before their first live birth (odds ratio, 1.6; 95%
CI, 1.1–2.3) than for women who had used it exclusively after their first live birth (odds
ratio, 1.0; 95% CI, 0.4–2.5). The association with genital use of talc was strongest for
serous invasive tumours (odds ratio, 1.7; 95% CI, 1.2–2.4). No association was observed
for endometrioid/clear-cell (odds ratio, 1.0; 95% CI, 0.7–1.6) or mucinous tumours (odds
ratio, 0.79; 95% CI, 0.4–1.4) (see Table 2.4).
     Wong et al. (1999) reported the results of a case–control study conducted at Roswell
Park Cancer Institute, Buffalo, NY (USA) of 499 cases treated between October 1982 and
October 1992 (largely those reported by Eltabbakh et al., 1998) and 755 hospital-based
controls. The controls were randomly selected from a registry of patients who were being
treated for non-gynaecological malignancies and were frequency-matched to cases by age
at diagnosis (within 5 years). The most common diagnoses among controls were
colorectal (43.3%) and skin cancers (34.5%) and leukaemia (17.7%). All participants
completed the self-administered, 44-item questionnaire that all patients were asked to
complete during the hospital admission process. All analyses were adjusted for age at
diagnosis, parity, oral contraceptive use, tobacco smoking, family history of ovarian
cancer, age at menarche, menopausal status, income, education, geographical location and
history of tubal ligation or hysterectomy. The analysis was restricted to 462 cases and
693 controls with information on perineal use of talc. ‘Ever’ use of talc (genital or non-
genital) was reported by 47.8% of the cases and 44.9% of the controls, while use of talc in
the genital or thigh area was reported by 34.0% of the cases and 32.2% of the controls.
There was no association between any method of talc use and the risk for ovarian cancer
after adjusting for several potentially confounding variables. The adjusted odds ratio for
talc use in the genital or thigh area was 1.0 (95% CI, 0.8–1.3). Duration of talc use was
similar in the cases and controls, and no association between talc use and the risk for
ovarian cancer was found for any duration category. No significant association was
observed between talc use and any of the major histological subtypes of ovarian cancer
(see Table 2.4); the odds ratio for serous cystadenocarcinoma was 1.2 (95% CI, 0.7–2.1).
No evidence was found of effect modification by history of tubal ligation or
hysterectomy. Among women who had not undergone tubal ligation or hysterectomy, the
odds ratio for the association between talc use and risk for ovarian cancer was 1.2 (95%
CI, 0.8–1.6) while among women who had undergone tubal ligation or hysterectomy, the
odds ratio was 0.8 (95% CI, 0.5–1.2). [Limitations of the study included the sparse
information on talc use. In addition, the use of hospital controls with non-gynaecological
malignancies may have caused selection bias. As noted in the earlier report by Eltabbakh
et al. (1998), the response rate to the questionnaire was low in this study population,
particularly among the patients with more advanced disease.]
     Ness et al. (2000) examined whether factors related to an inflammatory response of
the ovarian epithelium (such as exposure to talc, endometriosis, cysts and
hyperthyroidism) played a role in the risk for ovarian cancer. The study was conducted
376                        IARC MONOGRAPHS VOLUME 93

among 767 recently diagnosed cases of epithelial ovarian cancer and 1367 population-
based controls. Cases were aged 20–69 years and were identified between 1994 and 1998
at 39 hospitals in the Delaware Valley region (USA). Of 1253 potentially eligible cases,
61.2% were interviewed and included in the analysis. Reasons for excluding women from
the study included: diagnosis more than 6 months before the interview (n = 296), severe
illness or death (n = 69), unavailability of contact information (n = 15), physician refusal
(n = 14) or patient refusal (n = 92). Controls were identified through random-digit dialling
(for controls ≤ 65 years of age) and Health Care Financing Administration lists (for
controls 65–69 years of age) and were frequency-matched to cases by age and location of
residence. Overall, 72% of the eligible potential controls agreed to participate in the study.
A pathological review was conducted for a subset of the cases (n = 120). When compared
with the original diagnosis, the central review was 95% concordant for invasiveness and
82% concordant for cell type. The original pathological diagnosis was used in the analysis
for all cases. A standardized, 1.5-hour interview was conducted in the homes of the
participants to collect information on menstrual and reproductive history, sexual activity,
use of contraceptives, history and duration of talc use (genital and non-genital
applications and exposure via male sexual partners). Talc use was categorized according
to the method of application (never, feet, genital/rectal, sanitary napkins, underwear,
diaphragm or cervical cap, or male partner) and duration of exposure (< 1 year, 1–4 years,
5–9 years, > 10 years). Unconditional logistic regression adjusted for age, parity, race,
family history of ovarian cancer, oral contraceptive use, tubal ligation, hysterectomy and
lactation was used in all analyses. A history of talc use in the genital/rectal area was
reported by 161 cases [21.0%] and 219 controls [16.0%] to yield an adjusted odds ratio of
1.5 (95% CI, 1.1–2.0). Significant associations were also observed for the use of talc on
sanitary napkins (odds ratio, 1.6; 95% CI, 1.1–2.3) and on underwear (odds ratio,
1.7; 95% CI, 1.2–2.4). The use of talc on the feet, arms or breasts was associated with a
significant 40% increase in risk; however, women may also have used talc on more than
one area of the body, including the genital and/or rectal area. Use of talc on diaphragms or
cervical caps and use by a male sexual partner were not associated with the risk for
ovarian cancer. There was no clear trend between risk for ovarian cancer and increasing
duration of use of talc on the genital and/or rectal area or feet. Adjusted odds ratios of
2.0 (95% CI, 1.0–4.0), 1.6 (95% CI, 1.1–2.3), 1.2 (95% CI, 0.8–1.9) and 1.2 (95% CI,
1.0–1.5) were observed for < 1 year, 1–4 years, 5–9 years and ≥ 10 years of use,
respectively. [Limitations of this analysis included the sparse information on talc use. In
analyses of duration, the use of talc on the feet was also included as an exposure. The
relatively low participation rates among cases was also a limitation of the study.]
     Langseth and Kjaerheim (2004) (described in detail in Section 2.1.2(b)) evaluated the
association between employment in the pulp and paper industry in Norway and the risk
for ovarian cancer. In addition to the assessment of occupational exposure, information
was collected on hygienic use of talc and potential confounders for a subset of the cases
and controls during a personal interview conducted at the mills or by telephone. Exposure
to hygienic talc products was categorized as ever/never for personal use on diapers,
                                          TALC                                          377

sanitary napkins, underwear or husband’s use in the genital area. Thirty-five cases and
102 of the eligible controls or their next of kin agreed to an interview and an additional
19 women who were not cases were interviewed and included in secondary analyses as
supplementary controls. A family member completed the interview (due to the death of
the case or control) for 25 of the cases and 31 of the controls. Use of talc on the genital
area was reported by 12 cases and 53 controls to yield an odds ratio of 1.2 (95% CI, 0.4–
3.2). [The primary limitations of this analysis were the small number of cases, the small
percentage of cases and controls who were interviewed to obtain information on the
covariates of interest and use of surrogate respondents to obtain information on covariates
for the deceased cases and controls. The Working Group noted that hygienic exposure to
talc was assessed retrospectively in the nested case–control study.]
     Mills et al. (2004) evaluated the association between perineal exposure to talc and the
risk for ovarian cancer in an ethnically diverse population from 22 counties of central
California, USA. The study included 256 incident cases diagnosed between 1 January
2000 and 31 December 2001 and identified through two regional cancer registries using
rapid case ascertainment procedures and 1122 controls identified by random-digit
dialling. Controls were frequency-matched to the cases by age and ethnicity. Pathology
reports were reviewed centrally for a subset of the cases to confirm the diagnosis, subtype
and invasiveness of each cancer. Potential controls were ineligible for inclusion in the
study if they were under 18 years of age, were not a resident of the counties of interest or
if they had a history of epithelial ovarian cancer or bilateral oophorectomy. Among
652 cases identified during the study period, 263 (40.3%) were excluded due to: language
or hearing difficulties (n = 17), death (n = 76), physician refusal (n = 10), severe illness
(n = 41) or unavailability of current contact information (n = 119). Of the 389 eligible
cases who were contacted regarding participation in the study, 256 (65.8%) agreed to
participate and were interviewed. Of a total of 2327 potential controls, 740 (31.8%) were
excluded from the study due to: age (n = 80), location of residence (n = 21), language
difficulties (n = 10), previous bilateral oophorectomy (n = 252), severe illness (n = 19) or
change of address or telephone number or inability to contact the woman after repeated
attempts (n = 358). Of the 1587 potential controls who were contacted and found to be
eligible, 1122 (70.7%) agreed to participate and were interviewed. All cases and controls
were interviewed by telephone to obtain information on their medical history, covariates
of interest and history of perineal exposure to talc, including the frequency, duration and
calendar years of use. Information on talc use was unavailable for seven cases and
17 controls; thus, the final study population for this analysis included 249 cases and
1105 controls. For the final models, unconditional logistic regression adjusted for age,
race/ethnicity, duration of oral contraceptive use and breastfeeding was used. Additional
covariates considered to be potential confounders included family history of breast cancer
or ovarian cancer, parity, history of pregnancy, body mass index, hysterectomy, tubal
ligation and duration of postmenopausal use of hormones. A history of perineal talc use
was reported by 42.6% of the cases and 37.1% of the controls to yield an adjusted odds
ratio of 1.4 (95% CI, 1.0–1.9). A significant trend (P = 0.015) with increasing frequency
378                        IARC MONOGRAPHS VOLUME 93

of talc use was observed. The greatest risk for ovarian cancer was observed among
women with the highest frequency of use (odds ratio, 1.7 for use 4–7 times per week;
95% CI, 1.1–2.6). There was a borderline significant trend with increasing duration of use
(P = 0.045). The highest risk was observed among women with 4–12 years of use (odds
ratio, 1.9; 95% CI, 1.2–3.0) and elevated but non-significant risks were seen among
women with longer durations of use with odds ratios of 1.5 (95% CI, 0.9–2.3) and 1.2
(95% CI, 0.7–2.1) for 13–30 and > 30 years of use, respectively. A borderline significant
trend was noted for cumulative talc use (frequency times duration of use), although this
was also not clear-cut (P = 0.051). The highest risks were observed in the second and
third quartiles of cumulative talc use. When examined according to the time of use, the
risk was higher among women who had first used talc after 1975 (odds ratio, 1.9; 95% CI,
1.3–2.9) than among those who had first used talc before or during 1975 (odds ratio, 1.2;
95% CI, 0.8–1.8). Risk was also higher among women who were aged 20 years or more
at first talc use than among those who were under 20 years of age and among women who
initiated talc use after their first birth than among those who had some use before their
first birth. When time since last use was examined, women who had last used talc 1–
2 years previously had the highest risk (odds ratio, 2.4; 95% CI, 1.4–4.1); women who
had last used it 3–20 years previously had an elevated but non-significant risk for ovarian
cancer (odds ratio, 1.6; 95% CI, 0.9–2.7). Modification of the association between
perineal use of talc and risk for ovarian cancer by tubal ligation, hysterectomy, parity, oral
contraceptive use, postmenopausal use of hormones and body mass index was also
evaluated. Risk was higher among women who had not had tubal ligation (odds ratio, 1.5;
95% CI, 1.1–2.2) than among those who had (odds ratio, 0.9; 95% CI, 0.5–1.7), although
the interaction was not statistically significant. Risk was also higher among women who
had ever been pregnant (odds ratio, 1.4; 95% CI, 1.1–2.0) than among those who had
never been pregnant (odds ratio, 0.9; 95% CI, 0.4–2.3) and among women who had no
history of oral contraceptive use (odds ratio, 1.6; 95% CI, 1.0–2.6) than among those who
had used oral contraceptives (odds ratio, 1.3; 95% CI, 0.9–1.8). No evidence was found of
a modification of effect by hysterectomy status, body mass index or postmenopausal use
of hormones. [Limitations of this study included the low participation rate and relatively
small number of cases. In addition, pathology was not confirmed for all cases, which may
have resulted in some misclassification of histological subtype.]

2.3      Use of talc in pleurodesis

    The use of talc or iodized talc to produce pleurodesis began in the 1930s as a treatment
for recurrent spontaneous pneumothorax or pleural effusions. The therapy involves the
introduction of 0.5–10 g talc directly into the pleura using intrapleural injection. In recent
decades, the therapy has most commonly been restricted to use for the treatment of
malignant pleural effusions.
    An individual case report described a lung adenocarcinoma that was diagnosed
2 years after pleurodesis with iodized talc (Jackson & Bennett, 1973).
                                              TALC                                             379

     A survey was reported (Research Committee of the British Thoracic Association and
the Medical Research Council Pneumoconiosis Unit, 1979) of the long-term effects of
pleurodesis with talc and kaolin among a series of British patients who were followed for
14–40 years. The one talc mentioned (BP Indian Finex) was reported not to contain
fibrous amphiboles, but it was unclear if that was true of all the talcs used. Three lung
cancers were observed (2.14 expected, P > 0.3) among 210 talc pleurodesis patients. Two
of the lung cancer patients developed tumours on the opposite side from where treatment
had occurred (18-month and 19-year intervals between treatment and death). The third
patient had an oat cell carcinoma (site unknown) and died 32 years after treatment. No
cases of mesothelioma were reported.
     Viskum et al. (1989) reported on 99 Danish patients who had been treated in 1954–64
by pleurodesis with talc at doses that ranged from 0.5 to 4.9 g and who were followed for
at least 20 years. Three deaths from lung cancer occurred [expected number of cases not
provided], one on the side opposite from where treatment had occurred and two with no
origin reported. No cases of mesothelioma were reported. [The Working Group noted that
these reports are difficult to interpret because of the high prevalence of lung disease in the
patient groups, which could be related to risk factors such as tobacco smoking. The type
or source of talc used was not clear, although it was assumed to be pharmaceutical grade.
No case of mesothelioma was observed but the number of expected cases would probably
be very low.]

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     stomach and lung cancer among rubber workers: an analysis using internal controls and refined
     exposure assessment. Int J Epidemiol, 28:1037–1043. doi:10.1093/ije/28.6.1037.
     PMID:10661645
Straif K, Keil U, Taeger D et al. (2000). Exposure to nitrosamines, carbon black, asbestos, and talc
     and mortality from stomach, lung, and laryngeal cancer in a cohort of rubber workers. Am J
     Epidemiol, 152:297–306. doi:10.1093/aje/152.4.297. PMID:10968374
Thomas TL, Stewart PA (1987). Mortality from lung cancer and respiratory disease among pottery
     workers exposed to silica and talc. Am J Epidemiol, 125:35–43. PMID:3024482
Tzonou A, Polychronopoulou A, Hsieh C-C et al. (1993). Hair dyes, analgesics, tranquilizers and
     perineal talc application as risk factors for ovarian cancer. Int J Cancer, 55:408–410.
     doi:10.1002/ijc.2910550313. PMID:8375924
Viskum K, Lange P, Mortensen J (1989). Long term sequelae after talc pleurodesis for spontaneous
     pneumothorax. Pneumologie, 43:105–106. PMID:2717548
Wergeland E, Andersen A, Baerheim A (1990). Morbidity and mortality in talc-exposed workers.
     Am J Ind Med, 17:505–513. doi:10.1002/ajim.4700170408. PMID:2327417
Whittemore AS, Wu ML, Paffenbarger RS Jr et al. (1988). Personal and environmental
     characteristics related to epithelial ovarian cancer. II. Exposures to talcum powder, tobacco,
     alcohol, and coffee. Am J Epidemiol, 128:1228–1240. PMID:3195564
Wild, P. (2000) [An epidemiolgical mortality study in the Talc-producing industry: Study Report]
     (INRS/EE Report TMT), Paris, Institut National de la Recherche Scientifique (in French)
Wild P (2006). Lung cancer risk and talc not containing asbestiform fibres: a review of the
     epidemiological evidence. Occup Environ Med, 63:4–9. doi:10.1136/oem.2005.020750.
     PMID:16361399
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Wild P, Leodolter K, Réfrégier M et al. (2002). A cohort mortality and nested case-control study of
    French and Austrian talc workers. Occup Environ Med, 59:98–105. doi:10.1136/oem.59.2.98.
    PMID:11850552
Wong C, Hempling RE, Piver MS et al. (1999). Perineal talc exposure and subsequent epithelial
    ovarian cancer: a case-control study. Obstet Gynecol, 93:372–376. doi:10.1016/S0029-
    7844(98)00439-6. PMID:10074982
Wu ML, Whittemore AS, Paffenbarger RS Jr et al. (1988). Personal and environmental
    characteristics related to epithelial ovarian cancer. I. Reproductive and menstrual events and
    oral contraceptive use. Am J Epidemiol, 128:1216–1227. PMID:3195563
                                            TALC                                           383




               3. Studies of Cancer in Experimental Animals

    The Working Group identified an issue that relates to the interpretation of several of
the inhalation and intratracheal instillation studies of talc. A lesion that is frequently seen
in rats that have been exposed by inhalation to a range of poorly soluble particles such as
talc has been described variously as ‘proliferating squamous cyst’, ‘proliferative
keratinizing cyst’, ‘proliferating squamous epithelioma’, ‘benign cystic keratinizing
squamous-cell tumour’ or ‘cystic keratinizing squamous-cell tumour’. Various authors
have included this lesion in tumour counts, but the neoplastic nature of this lesion has
been debated (Kittel et al., 1993; Carlton, 1994; Mauderly et al., 1994; Boorman & Seely,
1995; Rittinghausen et al., 1997; Rittinghausen & Kaspareit, 1998); its relationship to
pulmonary neoplasia is uncertain.
    The Working Group noted that, in many of the studies of ‘talc’ described below, no or
limited characterization of the mineralogy of the sample employed was given, and, in
particular, that there was a lack of information on fibre content or particle size.

3.1      Oral administration

Rat
    Groups of 25 male and 25 female Wistar rats, 10 weeks of age, received about
50 mg/kg body weight (bw) per day of commercial talc [characteristics unspecified] in the
diet (average survival, 649 days) or standard diet alone for life (average survival,
702 days). No significant difference in tumour incidence was found in the treated animals
compared with control animals (Gibel et al., 1976).
    Groups of 16 male and 16 female Wistar-derived rats, 21–26 weeks of age, were fed
100 mg Italian talc (grade 00000; ready milled; mean particle size, 25 µm; containing
92% talc, 3% chlorite, 1% carbonate minerals and 0.5–1% quartz) per day per rat in the
diet for 5 months (talc-containing diet was actually given for 101 days) and were then
maintained on basal diet for life (average survival, 614 days). No differences in tumour
incidence were noted between treated animals and eight male and eight female control
animals fed basal diet throughout (average survival, 641 days) (Wagner et al., 1977). [The
Working Group noted the limited exposure period and the advanced age of the animals at
the start of the study.]
384                        IARC MONOGRAPHS VOLUME 93

3.2      Inhalation exposure

3.2.1    Mouse
     Groups of 47–49 male and 48–50 female B6C3F1 mice, 7 weeks of age, that were fed
an NIH-07 diet, were exposed by inhalation to aerosols containing 0, 6 or 18 mg/m3 MP
10–52 grade talc for 6 hours per day on 5 days per week for up to 104 weeks (dose
equivalent, 0, 2 or 6 mg/kg bw per day for male mice and 0, 1.3 or 3.9 mg/kg bw per day
for female mice). MP 10–52 grade is a high-purity microtalc (from a strip mine located in
Missouri State, USA) that has a maximal particle size of 10 µm and is reported to contain
no tremolite or any asbestiform minerals. After analysis, the talc was found to be free of
asbestos and almost free of silica. The average mass mean aerodynamic diameter
(MMAD) and the geometric standard deviation (GSD) of the talc aerosols were calculated
to be 3.3 ± 1.9 µm and 3.6 ± 2.0 µm for the 6- and 18-mg/m3 chambers, respectively. At
approximately week 70, difficulties were experienced in generating the talc aerosol, and
the chamber concentrations were substantially lower than the target concentrations over a
period of 12 weeks. Survival and final mean body weights of male and female mice
exposed to talc were similar to those of the controls, and no clinical findings were
attributed to exposure to talc. No significant increases in the incidence of neoplasms were
observed. The incidence of pulmonary neoplasms (males: 27%, 11% and 23%; females:
11%, 12% and 6%) was similar between exposed and control groups of mice. [The
Working Group noted that the incidence of alveolar/bronchiolar adenoma or carcinoma
combined in historical control B6C3F1 mice fed an NIH-07 diet in National Toxicology
Program inhalation studies was 26.8% for males and 10.1% for females] (National
Toxicology Program, 1993).

3.2.2    Rat
     Two groups of 12 male and 12 female Wistar-derived rats, 6–8 weeks of age, were
exposed by inhalation to a mean respirable dust concentration of 10.8 mg/m3 Italian talc
(grade 0000; ready milled; mean particle size, 25 µm in diameter; containing 92% talc,
3% chlorite, 1% carbonate minerals and 0.5–1% quartz) for 7.5 hours per day on 5 days a
week for 6 or 12 months (cumulative exposures, 8200 and 16 400 mg/m3 × h,
respectively). Ten days after the end of each exposure period, six rats per group were
killed; 12 rats per group died and two rats per group were unaccounted for; the remaining
four rats per group were killed 1 year after the end of the exposure period. No differences
were noted in the incidence of lung tumours compared with 24 male and 24 female
untreated controls (Wagner et al., 1977). [The Working Group noted the limited number
of animals allowed to survive longer than 12 months after the end of each exposure
period.]
     Groups of 49 or 50 male and 50 female Fischer 344/N rats, 6–7 weeks of age, were
exposed by inhalation to aerosols of 0, 6 or 18 mg/m3 MP 10–52 grade talc (see Section
3.2.1) for 6 hours per day on 5 days per week until mortality in any exposure group
                                          TALC                                          385

reached 80% (113 weeks for males and 122 weeks for females; dose equivalent, 0, 2.8 or
8.4 mg/kg bw per day for males GSD and 0, 3.2 or 9.6 mg/kg bw per day for females).
The average MMAD and the GSD of the talc aerosols were calculated to be 2.7 ± 1.9 μm
and 3.2 ± 1.9 μm for the 6- and 18-mg/m3 chambers, respectively. At week 11, the
chamber concentration for the 18-mg/m3 group varied from approximately 30 to
40 mg/m3 for a period of 7 weeks because of difficulties with the systems used to monitor
aerosol concentration. In addition, at approximately week 70, difficulties were
experienced in generating the talc aerosol for a period of 12 weeks during which the
chamber concentrations were substantially lower than the target concentrations. The
survival of treated male and female rats was similar to that of the controls. Mean body
weights of rats exposed to 18 mg/m3 were slightly lower than those of controls after week
65. Absolute and relative lung weights of male rats exposed to 18 mg/m3 were
significantly greater than those of controls at the 6-, 11- and 18-month interim evaluations
and at the end of the lifetime study, while those of female rats exposed to 18 mg/m3 were
significantly greater at the 11-, 18- and 24-month interim evaluations and at the end of the
lifetime study. Exposure to talc produced a spectrum of inflammatory, reparative and
proliferative processes in the lungs. The principal toxic lesions observed included chronic
granulomatous inflammation, alveolar epithelial hyperplasia, squamous metaplasia,
squamous cysts and interstitial fibrosis of the lung. The authors considered that the
squamous cysts represented a form of squamous metaplasia. The incidence of
alveolar/bronchiolar adenoma and carcinoma (combined) in female rats was: control, 1/50
(carcinoma, 0/50); low-dose, 0/48; high-dose, 13/50 (carcinoma, 5/50) and was
significantly greater (P < 0.001) in the high-dose group than in controls (carcinoma,
P = 0.028). The incidence of pulmonary neoplasms in exposed male rats was similar to
that in controls. Adrenal medulla pheochromocytomas (benign and malignant combined)
occurred with a significantly positive trend in males (control, 26/49; low-dose, 32/48;
high-dose, 37/47; P = 0.007) and females (control, 13/48; low-dose, 14/47; high-dose,
23/49; P = 0.014), and the incidence in the high-dose groups was significantly greater
than that in controls (P = 0.006 for males, P = 0.024 for females). The incidence of
malignant pheochromocytomas in females was: control, 0/48; low-dose, 1/47; high-dose,
10/49 (P = 0.001). Although adrenal medulla hyperplasia occurred with similar frequency
among exposed and control females, the incidence of hyperplasia in exposed males was
significantly lower than that in controls (National Toxicology Program, 1993). [The
Working Group noted that some authors have indicated that stress and hypoxia may lead
to a proliferation of chromaffin cells and eventually to pheochromocytomas. An increase
in the incidence of these tumours was also observed in several other National Toxicology
Program studies that used particulates and the same rat strain in which the background
incidence of this type of tumour was quite high (Ozaki et al., 2002; Melnick et al., 2003).
The Working Group also noted that this type of tumour was not reported in particle
inhalation studies other than those of the National Toxicology Program, and hence felt
that this increase may not be related to talc.]
386                        IARC MONOGRAPHS VOLUME 93

3.2.3     Hamster
    In a lifetime experiment, three groups of 50 male and 50 female Syrian golden
hamsters, 4 weeks of age, were exposed by inhalation to an aerosol of talc baby powder
that was prepared from Vermont talc by flotation (95% w/w platy talc with trace
quantities of magnesite, dolomite, chlorite and rutile) for 3, 30 or 150 minute per day on
5 days a week for 30 days. The mean aerosol concentration was 37.1 mg/m3, with a
measurable respiratory fraction of 9.8 mg/m3 and a MMAD of 4.9 µm. A sham-exposed
group comprised 25 males and 25 females. Two further groups of hamsters, 7 weeks of
age, were exposed to talc aerosol for 30 or 150 minute per day for 300 days. The mean
aerosol concentration was 27.4 mg/m3, with a measurable respiratory fraction of
8.1 mg/m3 and a MMAD of 6.0 µm. Another sham-exposed group comprised 25 males
and 25 females. The survivors of the last two talc-exposed groups were killed at the age of
20 months. At that time, 20% of the males were still alive and all females were dead. No
primary tumours were observed in the lungs in any of the hamsters, although the
incidence of alveolar-cell hyperplasia in the groups given talc aerosol for 30 or
150 minutes per day for 300 days was 25% compared with 10% in the control group
(Wehner et al., 1977, 1979). [The Working Group noted the short daily exposure time and
the high mortality rate.]

3.3       Intratracheal administration

Hamster
    Four groups of 24 male and 24 female Syrian golden hamsters, 9 weeks of age,
received 18 weekly intratracheal instillations of 3 mg talc (USP grade; silica oxide, 61–
63%; magnesium oxide, 32–34%; other dusts, 0.85–1.06%; 93.3% < 25 µm in diameter)
in 0.2 mL saline with or without 3 mg benzo[a]pyrene, or 0.2 mL saline alone or were
untreated. The animals were allowed to live out their lifespan (average 50% survival, 46–
55 weeks). No respiratory tract tumours were observed in the talc-treated, saline-treated or
untreated groups. Malignancies were observed in 33/45 animals treated with talc plus
benzo[a]pyrene (Stenbäck & Rowlands, 1978). [The Working Group noted the short
survival of the animals.]

3.4       Subcutaneous administration

Mouse
    Fifty female R3 mice, 3–6 months of age, were given single subcutaneous injections
of 0.2 mL of a mixture of 8 g talc [type unspecified] and 20 g peanut oil (delivered dose,
about 80 mg) and were observed for life (average 50% survival, 596 days). No local
tumour was observed (Neukomm & de Trey, 1961).
                                           TALC                                           387

    In a study reported in an abstract, female Marsh mice, 3 months of age, received
single subcutaneous injections of 20 mg USP talc and were observed for 18–21 months.
No tumour developed at the injection site in 26 treated animals or in 24 saline-injected
controls (Bischoff & Bryson, 1976).

3.5      Intraperitoneal administration

3.5.1    Mouse
     In a study that investigated the response to intraperitoneally injected asbestos, control
groups of 12, four, five, six, five and 12 white male mice [age unspecified] were injected
intraperitoneally with a 0.5-mL suspension (50%) of talc in saline and killed 26, 57, 112,
147, 170 and 343 days after injection, respectively. Talc was described as 6505–147–
0000 Talc, USP V (no further analysis was made). Histopathological examination was
performed, and no mesotheliomas or other neoplasms were reported (Jagatic et al., 1967).
     In a study reported as an abstract, female Marsh mice, 3 months of age, received a
single intraperitoneal injection of 20 mg USP talc and were observed for 18–21 months.
Intraperitoneal lymphoid tumours occurred in 5/22 treated animals and in 6/28 saline-
treated controls (Bischoff & Bryson, 1976).
     Fourty Swiss albino mice [sex unspecified], 6 weeks of age, received a single
intraperitoneal injection of 20 mg ground commercial talc [type unspecified] in 1 mL
saline. Within 6 months, 16 animals had died. In the 24 survivors allowed to live out their
normal lifespan, three peritoneal mesotheliomas were observed, compared with
3/46 saline-treated controls (Özesmi et al., 1985). [The Working Group noted the
occurrence of mesotheliomas in saline-treated animals.]

3.5.2    Rat
     A group of 40 female Wistar rats, 8–12 weeks of age, received four intraperitoneal
injections of 25 mg granular talc [characteristics unspecified] in 2 mL saline at weekly
intervals. A group of 80 female rats was injected with 2 mL saline alone and served as
controls. The rats were observed until spontaneous death or when killed in moribund
state. A mesothelioma was observed in 1/36 talc-exposed rats after 587 days compared
with none in 72 controls (Pott et al., 1974, 1976a,b).
     In a study reported as an abstract, female Evans rats, 3 months of age, received a
single intraperitoneal injection of 100 mg USP talc and were observed for 18–21 months.
Of the treated rats, 3/27 developed tumours (one lymphosarcoma and one reticulum-cell
sarcoma in the peritoneal cavity, one cystadenoma of the liver) compared with none of
26 saline-treated controls (Bischoff & Bryson, 1976).
388                        IARC MONOGRAPHS VOLUME 93

3.6      Intrapleural and intrathoracic administration

3.6.1    Mouse
    In a study reported as an abstract, male Marsh mice, 3 months of age, received a
single intrathoracic injection of 10 mg USP talc. After 18–21 months, 5/47 treated mice
had tumours (two adenocarcinomas and three lymphoid tumours of the lung) compared
with none of 48 saline-injected controls (Bischoff & Bryson, 1976).

3.6.2    Rat
     In a study reported as an abstract, female Evans rats, 3 months of age, received single
intrathoracic injections of 50 mg USP talc. After 18–21 months, intrathoracic reticulum-
cell sarcomas or lymphomas were observed in 7/30 talc-treated rats, 8/32 saline-treated
rats and 7/28 untreated controls (Bischoff & Bryson, 1976).
     In a lifetime study, a group of 24 male and 24 female Wistar-derived rats, 8–14 weeks
of age, received a single intrapleural injections of 20 mg Italian talc (grade 00000; ready
milled; mean particle size, 25 µm; containing 92% talc, 3% chlorite, 1% carbonate
minerals and 0.5–1% quartz) in 0.4 mL saline. The mean survival time of the treated rats
(655 days) was similar to that of 24 male and 24 female controls (691 days) that were
injected with saline. No mesothelioma was detected in either group; one small pulmonary
adenoma was found in one treated rat that died 25 months after injection (Wagner et al.,
1977).
     Following thoracotomy, groups of 30–50 female Osborne-Mendel rats, 12–20 weeks
of age, received intrapleural implantations of 40 mg of one of seven grades of refined
commercial talc from separate sources in hardened gelatin. The rats were followed for
2 years, at which time survivors were killed. The incidence of pleural sarcomas was: talc
1, 1/26; talc 2, 1/30; talc 3, 1/29; talc 4, 1/29; talc 5, 0/30; talc 6, 0/30; talc 7, 0/29;
untreated controls, 3/488 (0.6%); and controls that received implants of ‘non-fibrous’
materials described by the authors as ‘non-carcinogenic’, 17/598 (3%) (Stanton et al.,
1981).

3.7      Ovary implantation

Rat
    In a study that investigated the effect of implanted talc on the rat ovary, a group of
10 female Sprague-Dawley rats, 10–15 weeks of age, received implants of 100 µL of a
talc suspension in saline (100 mg/mL) onto the surface of the ovary by intrabursal
injection. The talc was described as Italian 00000 (particle size, 0.3–14 µm) and contained
no asbestos. Three sham-operated and three sham-treated control animals were included.
Animals were killed after 12 months and histopathological examination of the ovaries
was performed. Small focal areas of papillary change that were considered to be
                                               TALC                                              389

preneoplastic changes were seen in the surface epithelium of 4/10 treated animals
(0/6 controls). No neoplasms were reported (Hamilton et al., 1984). [The Working Group
noted that groups of animals implanted for 1, 3, 6 or 18 months were also included, but no
results were reported for any of these groups.].

3.8       References
Bischoff F, Bryson G (1976). Talc at the rodent intrathoracic, intraperitoneal, and subcutaneous
     sites (Abstract No.1). Proc Am Assoc Cancer Res, 17:1.
Boorman GA, Seely JC (1995). The lack of an ovarian effect of lifetime talc exposure in F344/N
     rats and B6C3F1 mice. Regul Toxicol Pharmacol, 21:242–243. doi:10.1006/rtph.1995.1035.
     PMID:7644712
Carlton WW (1994). “Proliferative keratin cyst,” a lesion in the lungs of rats following chronic
     exposure       to    para-aramid     fibrils.    Fundam        Appl     Toxicol,     23:304–307.
     doi:10.1006/faat.1994.1108. PMID:7526997
Gibel W, Lohs K, Horn KH et al. (1976). [Experimental study on cancerogenic activity of asbestos
     filters. Arch Geschwulstforsch, 46:437–442 (in German). PMID:999453
Hamilton TC, Fox H, Buckley CH et al. (1984). Effects of talc on the rat ovary. Br J Exp Pathol,
     65:101–106. PMID:6696826
Jagatic J, Rubnitz ME, Godwin MC, Weiskopf RW (1967). Tissue response to intraperitoneal
     asbestos with preliminary report of acute toxicity of heat-treated asbestos in mice. Environ Res,
     1:217–230. doi:10.1016/0013-9351(67)90014-X. PMID:4303313
Kittel B, Ernst H, Dungworth DL et al. (1993). Morphological comparison between benign
     keratinizing cystic squamous cell tumours of the lung and squamous lesions of the skin in rats.
     Exp Toxicol Pathol, 45:257–267. PMID:7508775
Mauderly JL, Snipes MB, Barr EB et al. (1994). Pulmonary toxicity of inhaled diesel exhaust and
     carbon black in chronically exposed rats. Part I: Neoplastic and nonneoplastic lung lesions. Res
     Rep Health Eff Inst, 68:1–75, discussion 77–97. PMID:7530965
Melnick RL, Bucher JR, Roycroft JH et al. (2003). Carcinogenic and toxic effects of inhaled, non-
     fibrous, poorly soluble particulates in rats and mice contradict threshold lung cancer
     hypotheses that are dependent on chronic pulmonary inflammation. . Eur J Oncol., 8:177–186.
National Toxicology Program (1993). Toxicology and Carcinogenesis Studies of Talc (CAS No.
     14807–96–6) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). (Tech Rep Ser 421),
     Research Triangle Park, NC.
     Available at: http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr421.pdf
Neukomm S, de Trey M (1961) [Study of possible carcinogenic and/or co-carcinogenic
     brightening agents.] Med Exp, 4:298–306 (in French).
Ozaki K, Haseman JK, Hailey JR et al. (2002). Association of adrenal pheochromocytoma and
     lung pathology in inhalation studies with particulate compounds in the male F344 rat–
     the National Toxicology Program experience. Toxicol Pathol, 30:263–270.
     doi:10.1080/019262302753559605. PMID:11950170
Özesmi M, Patiroglu TE, Hillerdal G, Özesmi C (1985). Peritoneal mesothelioma and malignant
     lymphoma in mice caused by fibrous zeolite. Br J Ind Med, 42:746–749. PMID:2998433
390                           IARC MONOGRAPHS VOLUME 93

Pott F, Dolgner R, Friedrichs K-H, Huth F (1976b). [The oncogenic effect of fibrous dust. Animal
     experiments and their relationship with human carcinogenesis]. Ann Anat Pathol, 21:237–246
     (in French). PMID:970688
Pott F, Friedrichs K-H, Huth F (1976a). [Results of animal experiments concerning the
     carcinogenic effect of fibrous dusts and their interpretation with regard to the carcinogenesis in
     humans.] Zentralbl Bakteriol Orig B, 162:467–505 (in German). PMID:185852
Pott F, Huth F, Friedrichs KH (1974). Tumorigenic effect of fibrous dusts in experimental animals.
     Environ Health Perspect, 9:313–315. doi:10.2307/3428305. PMID:4377876
Rittinghausen S, Kaspareit J (1998). Spontaneous cystic keratinizing epithelioma in the lung of a
     Sprague-Dawley rat. Toxicol Pathol, 26:298–300. doi:10.1177/019262339802600218.
     PMID:9547872
Rittinghausen S, Mohr U, Dungworth DL (1997). Pulmonary cystic keratinizing squamous cell
     lesions of rats after inhalation/instillation of different particles. Exp Toxicol Pathol, 49:433–
     446. PMID:9495643
Stanton MF, Layard M, Tegeris A et al. (1981). Relation of particle dimension to carcinogenicity
     in amphibole asbestoses and other fibrous minerals. J Natl Cancer Inst, 67:965–975.
     PMID:6946253
Stenbäck F, Rowlands J (1978). Role of talc and benzo(a)pyrene in respiratory tumor formation.
     An experimental study. Scand J Respir Dis, 59:130–140. PMID:684384
Wagner JC, Berry G, Cooke TJ et al. (1977). Animal experiments with talc. In: Walton WH,
     McGovern B, eds, Inhaled Particles, Vol. IV, Part 2, Oxford, Pergamon Press, pp. 647–
     654.
Wehner AP, Stuart BO, Sanders CL (1979). Inhalation studies with Syrian golden hamsters. Prog
     Exp Tumor Res, 24:177–198. PMID:538242
Wehner AP, Zwicker GM, Cannon WC (1977). Inhalation of talc baby powder by hamsters. Food
     Cosmet Toxicol, 15:121–129. doi:10.1016/S0015-6264(77)80317-9. PMID:873404
                                         TALC                                         391




                  4. Mechanistic and Other Relevant Data

     The general principles of inhalation, deposition, clearance and retention of poorly
soluble particles that have low toxicity are discusssed in the Monograph on carbon black
in this volume.

4.1      Humans

4.1.1    Deposition, retention and clearance
    Talc particles have been found at autopsy in the lungs of patients with ‘talc
pneumoconiosis’ (Schepers & Durkan, 1955a; Seeler, 1959; Kleinfeld et al., 1963;
Abraham & Brambilla, 1980; Berner et al., 1981; Vallyathan & Craighead, 1981). Talc,
in the form of platy or elongated particles, has been found at autopsy in the lungs of
urban residents, farmers and asbestos miners (Seeler, 1959; Langer et al., 1971; Pooley,
1976; Gylseth et al., 1984). Talc has been reported to be concentrated in lung scar
tissue (Yao et al., 1984). Clinically, intrapleural instillation of talc is used to induce
pleural adhesions in cases of pleural effusion and pneumothorax (Rodriguez-Panadero
& Antony, 1997).
    Churg and Wiggs (1985) used transmission electron microscopy and energy
dispersive X-ray spectroscopy to analyse the total fibrous and non-fibrous mineral
content of the lungs of a group of 14 male smokers who had lung cancer but no
history of occupational exposure to dust. A group of 14 control men were matched by
age, smoking history and general occupational class. The average concentrations of
mineral fibres and non-fibrous particles were nearly fourfold and approximately
twofold higher, respectively, in the group with cancer than in the controls. Kaolinite,
talc, mica, feldspars and crystalline silica comprised the majority of fibrous and non-
fibrous particles in both groups.
    In a subsequent study, Churg and Wiggs (1987) examined the distribution of
mineral fibres in the lungs of 10 male smokers who did not have lung cancer or a
history of occupational exposure to dust. The subjects were all over 50 years of age at
death and had a smoking history that ranged from 15 to 100 pack–years (mean,
45±24 pack–years). The primary minerals identified were kaolinite, silica and mica
and accounted for 64% of the fibres; feldspars and talc accounted for 9 and 7%,
respectively. There was a significant correlation between smoking history and particle
concentration (number of particles per gram of tissue) in the upper lobes. The
diameters (mean±standard deviation [SD]) of talc particles in the upper and lower
lobes were 1.2±0.9 μm and 0.9±1.0 μm, respectively.
    Dumortier et al. (1989) used analytical electron microscopy to examine non-
fibrous particle content in the bronchoalveolar lavage fluid of 51 occupationally
392                        IARC MONOGRAPHS VOLUME 93

exposed subjects, six of whom were talc millers. In the latter group, two workers had
almost exclusively talc in their lavage fluid, while the others had about 60% talc and
40% chlorite. In other workers, talc generally accounted for <3% of the particles in
lavage fluid. It was noted that, although the exposure of one of the millers had ceased
21 years before the examination, talc particles were still present in his lavage fluid.
     Talc particles have been found in stomach tumours from Japanese men
(Henderson et al., 1975), possibly due to ingestion of talc-treated rice (Merliss,
1971a,b). Talc particles, but apparently no other insoluble particles, were found in the
subserosal stroma of hernia sacs, possibly due to ingestion of medications in which
talc is present as a filler (Pratt et al., 1985). Anani et al. (1987) reported the presence of
talc fibres in the intestinal wall of a 46-year-old patient who had severe intestinal pain
and was diagnosed with intestinal talcosis. A possible source of exposure was the talc
contained in oral medications against tuberculosis, which the patient had taken nearly
20 years earlier over a period of 22 months (total intake of talc, 183 g).
     Talc is often present as a filler in some materials used by drug addicts, which
results in wide dissemination of talc particles to the lungs (Groth et al., 1972; Lamb &
Roberts, 1972; Farber et al., 1981; Crouch & Churg, 1983), spleen, kidney, liver, brain,
heart, adrenal and thyroid glands (Groth et al., 1972) and even the retina (AtLee,
1972). In the lungs, most of the talc particles are found within the vessels of the
alveolar walls, and are almost invariably associated with marked foreign-body
granulomas (Crouch & Churg, 1983). The talc particles found in the lungs are larger
after intravenous injection than after inhalation (Abraham & Brambilla, 1980) (see
Section 4.1.2 for a discussion of the associated toxic effects).
     In view of epidemiological evidence of a possible association between talc use for
perineal hygiene and an increased risk for ovarian cancer (see Section 2), several
studies have been conducted in women to determine potential retrograde movement
of particles through the reproductive tract to the ovaries. These studies involved
women who were about to undergo gynaecological surgery, mostly for diseases or
complications of the reproductive tract and organs. Therefore, broad interpretations
with regard to healthy women may be limited.
     Egli and Newton (1961) found that inert carbon particles deposited in the vagina in
two of three patients travelled to the fallopian tubes in about 30 minutes. De Boer
(1972) concluded that Indian ink deposited below the level of the cervix is unlikely to
travel quickly through the reproductive tract. In contrast, the findings of Venter and
Iturralde (1979) and Mostafa et al. (1985) suggested that retrograde transport to the
fallopian tubes is possible. Henderson et al. (1971) reported the actual presence of talc
in histological specimens from 10 of 13 ovarian tumours, 12 of 21 cervical tumours
and five of 12 normal ovarian tissues. Subsequently, Henderson et al. (1979) and
Heller et al. (1996) provided further evidence of the presence of talc in the ovaries of
women who had purportedly had perineal exposure to talc. However, in the latter
study, no relation was found between talc-particle counts and reported perineal use of
talc.
                                          TALC                                         393

4.1.2    Toxic effects
     The toxic effects of talc in humans are dependent on the route and dose of
administration and the physicochemical properties of the talc. In addition, talc products
commonly contain other potentially toxic minerals (see Section 1).
     Talc pneumoconiosis is somewhat more prevalent and severe among people who are
exposed to talc that contains asbestiform minerals than among those who are exposed to
talc with no such impurities (Kleinfeld et al., 1963). The form of this pneumoconiosis
varies widely, from a simple asymptomatic type (Vallyathan & Craighead, 1981) to
disabling conglomerate pneumoconiosis (Hunt, 1956; Graham & Gaensler, 1965; Miller
et al., 1971). Mixed-dust pneumoconiosis is frequently seen, including silicosis,
asbestosis and occasionally other forms (Kleinfeld et al., 1963; Mark et al., 1979).
     Several early reports described ‘talcum powder granuloma’ that arose from the use of
talc on surgical gloves (reviewed in Eiseman et al., 1947). Subsequent reports of cases
have documented a variety of surgical complications, including adhesions,
pseudotumours and sinus tracts that were attributable to exposure to talc (Lichtman et al.,
1946; Eiseman et al., 1947; reviewed by Hollinger, 1990). Both skin granulomas and talc
pneumoconiosis have been reported after liberal use of talc on the body (Tye et al., 1966;
Nam & Gracey, 1972; Wells et al., 1979; Tukiainen et al., 1984; Wehner, 1994).
     Respiratory distress syndrome, which can be fatal, has been described in children
following massive accidental inhalation of talcum powder (Cless & Anger, 1954; Molnar
et al., 1962; Lund & Feldt-Rasmussen, 1969; Gould & Barnardo, 1972) and in adult
patients after talc pleurodesis (Rehse et al., 1999).
     A variety of pathological effects arise from the intravenous use by drug addicts of
products that contain talc. These include micronuclear pulmonary opacities (Hopkins &
Taylor, 1970; Arnett et al., 1976; Waller et al., 1980), angiothrombotic pulmonary
hypertension (Wendt et al., 1964; Paré et al., 1979; Waller et al., 1980) and conglomerate
pulmonary lesions (Sieniewicz & Nidecker, 1980; Crouch & Churg, 1983). In addition,
retinopathy, cerebral microembolization and granulomas of the liver, lymph nodes and
kidneys have been reported (Min et al., 1974; Paré et al., 1979; Carman, 1985).
     A series of cross-sectional studies reported from the New York State Department of
Labour (Kleinfeld et al., 1955, 1963, 1964, 1973) have documented talc pneumoconiosis
in talc miners and millers, especially among tremolitic talc workers. The cases were
associated with pleural plaques, restrictive or obstructive breathing disorders and
decreased vital capacity of the lungs. The prevalence of disease was lower among those
with lower cumulative exposure to dust and among those who processed granular rather
than fibrous talc.
     A series of cross-sectional studies that described talc pneumoconiosis in workers in
talc mining, milling and manufacture in Italy (Rubino et al., 1963; Tronzano et al., 1965)
found that the prevalence was related to extent and duration of exposure and that talcs
contaminated with tremolite, serpentine and quartz were associated with significant
pneumoconiosis.
394                        IARC MONOGRAPHS VOLUME 93

     One representative, well-controlled study among 80 workers exposed in the rubber
industry to Vermont talc, which is reported to have a low content of silica and fibres,
showed significantly increased respiratory symptoms, impaired ventilatory function and
increased respiratory morbidity, but no radiographic abnormality (Fine et al., 1976).
     There has been some concern that talc may cause adult respiratory distress syndrome
when instilled into the pleural space for pleurodesis (Rinaldo et al., 1983; Bouchama et
al., 1984; Kennedy et al., 1994; Rehse et al., 1999; Light, 2000). Relatively recent cases
were observed when talc was both insufflated and used as a slurry (Brant & Eaton, 2001;
Scalzetti, 2001). However, other case series did not report the development of this disease
(Weissberg & Ben-Zeev, 1993; Rodriguez-Panadero & Antony, 1997; Sahn, 2000; Ferrer
et al., 2001, 2002; Cardillo et al., 2006). Many of the patients in the case reports had co-
morbid conditions. [The Working Group noted that the talc used in these reports was not
always characterized mineralogically and may have contained contaminants.]
     The role of exposure to talc in the development of ovarian cancer has raised concerns
(see Section 2). The normal ovarian epithelium is known to express several mucins that
are protective against epithelial inflammation and injury (Lalani et al., 1991; Gipson
et al., 1997; Ness & Cottreau, 1999; Taylor-Papadimitriou et al., 1999; Ness et al., 2000;
La Vecchia, 2001). Several epithelial cancers, such as breast and ovarian cancer, express
mucin (MUC-1) which is upregulated and aberrantly glycosylated in many carcinomas
(Taylor-Papadimitriou et al., 1999).
     Cramer et al. (2005) examined the association between the characteristics of women
with no previous diagnosis of ovarian cancer and levels of antibodies to MUC-1, a protein
that is expressed by normal epithelial cells and overexpressed by ovarian cancer cells. The
study participants were 705 controls from a case–control study of ovarian cancer
conducted in Massachusetts and New Hampshire (USA) between 1998 and 2003. Plasma
specimens collected from participants at enrolment into the study were analysed for anti-
MUC-1 antibody levels using an enzyme-linked immunosorbent assay. Forty-eight cases
of ovarian cancer with pre-operative blood specimens were also included in additional
analyses; further 668 cases of ovarian cancer were included in the analyses to evaluate
risk factors for ovarian cancer. Multivariable logistic regression, Spearman rank
correlations and generalized linear models were used in the statistical analyses to
determine which characteristics were associated with anti-MUC-1 antibody production
and which were associated with the risk for ovarian cancer. Women who reported no
previous genital use of talc were more likely to have antibodies to MUC-1 than women
who had a history of regular genital exposure to talc (38.1% versus 28.6%; P = 0.04). In
addition, there was a borderline significant trend between frequency of talc use and lower
anti-MUC-1 antibody levels (P = 0.11), after adjustment for other characteristics that
affect antibody levels. Several conditions associated with increased antibody production
were associated with a decreased risk for ovarian cancer. The authors concluded that these
findings suggest that the presence of anti-MUC1 antibodies is inversely correlated with
risk for ovarian cancer. [Limitations of this study included the potential for bias in the
participants’ recollection of their genital use of talc, due to the case–control study design.
                                           TALC                                           395

In addition, antibody levels in the cases and controls may not be comparable, since the
presence of a cancer may affect anti-MUC-1 antibody levels.]

4.2      Experimental systems
4.2.1    Deposition, retention and clearance
     The deposition, translocation and clearance of talc was investigated in 44 female
golden Syrian hamsters (10 weeks of age) that were exposed by nose-only inhalation for
2 hours to 40–75 mg/m3 neutron-activated talc (Johnsons’s Baby Powder®, lot 228p;
median aerodynamic diameter, 6.4–6.9 µm). The powder was high-grade cosmetic talc
and consisted of 95% (w/w) platy talc mineral (Wehner et al., 1977a). Alveolar
deposition was approximately 20–80 μg, which represented 6–8% of the inhaled amount.
The retention half-time of the talc deposited in the alveoli was 7–10 days, and alveolar
clearance was reported to be essentially complete 4 months after exposure. No
translocation of talc to liver, kidneys, ovaries or other parts of the body was found
(Wehner et al., 1977b). [The Working Group noted that the unusually short clearance
time may be related to limitations in the sensitivity of the detection methods and the large
size of the particles used.]
     In rats exposed for 7.5 h per day on 5 days a week to aerosols of Italian talc (mean
concentration of respirable dust [not further defined], 10.8 mg/m3), the mean amounts of
talc retained in the lung were 2.5, 4.7 and 12.2 mg per animal following exposures for 3, 6
and 12 months, respectively. These levels were approximately proportional to the
cumulative exposures (Wagner et al., 1977). In rats exposed for 6 hours per day on 5 days
a week for 4 weeks to 2.3, 4.3 and 17 mg/m3 respirable talc, the amounts retained in the
lung at the end of exposure were 77, 187 and 806 µg talc/g lung, respectively (Hanson et
al., 1985).
     Lung burdens of talc were determined in groups of 10 male and 10 female Fischer
344 rats and B6C3F1 mice following exposure to asbestos-free talc for 6 hours per day on
5 days a week for 4 weeks. In rats exposed to 0, 2.3, 4.3 and 17 mg/m3, average lung
burdens were 0, 0.07, 0.17 and 0.72 mg talc/g lung, respectively. In mice exposed to 0,
2.2, 5.7 and 20.4 mg/m3, average lung burdens of 0, 0.10, 0.29 and 1.0 mg talc/g lung,
respectively, were observed. When normalized to the exposure concentration, the lung
burden in mice was greater than that in rats and the normalized burden in rats increased
with increasing exposure concentration (Pickrell et al., 1989).
     Conflicting data exist on systemic distribution following intrapleural instillation of
talc (i.e. talc pleurodesis) in rats. Following administration of 10 or 20 mg talc [particle
size unspecified] to rats (20 per group), talc was identified in the chest wall, lungs, heart,
brain, spleen and kidneys. The authors concluded that talc is rapidly absorbed through the
pleura and reaches the systemic circulation and organs 24 hours after administration
(Werebe et al., 1999). However, following instillation of 40 mg talc (median particle size,
31 μm) into 33 rats randomly assigned to autopsy 24 or 72 hours later, talc particles were
396                        IARC MONOGRAPHS VOLUME 93

observed in only a few extrapulmonary organs, i.e. the brain, spleen and liver, but not the
kidneys (Fraticelli et al., 2002).
     The systemic distribution of talc was investigated in rabbits following talc pleurodesis
in two studies. In one study (Ferrer et al., 2002), 10 rabbits received 200 mg/kg bw
8.4-μm asbestos-free talc particles and 10 received 200 mg/kg bw 12-μm talc particles.
Five animals from each group were killed after 24 hours and five at 7 days after
instillation. A tendency was seen for increased extrapulmonary distribution of the smaller
particles, which were identified in the pericardium of 0/5 and 3/5 rabbits at 24 hours and
7 days, respectively. For the larger particles, one of five animals had talc in the
pericardium at each time-point. Particles were identified in the liver of three of five
animals exposed to the smaller particles 7 days after instillation; other groups had no
particles in the liver. Small particles were found in the kidney of only 1/5 animals
24 hours after instillation. Both particle types were found in the spleen of 1/5 animals
24 hours after instillation. The results indicate that talc reached the lung parenchyma by
breaking the mesothelial and elastic layer and that mobility was greater for the smaller
particles.
     In the other study, Montes et al. (2003) performed talc pleurodesis in rabbits (20 per
group) at doses of 50 and 200 mg/kg bw of the small-particle talc used in the study by
Ferrer et al. (2002). Doses were chosen to simulate treatment of a 60-kg patient with
amounts of 3 and 12 g talc. The lung parenchyma of two and 14 rabbits of the low-dose
and high-dose groups, respectively, contained talc. In the high-dose group, six of the
animals had talc in the pericardium and five had talc in the liver; talc was not detected in
these organs in the low-dose group. The results show that the systemic distribution of talc
was dose-dependent.
     In studies in rats, mice, guinea-pigs and hamsters that used radioactive tracer
techniques, no intestinal absorption or translocation of ingested talc to the liver or kidneys
was detected (Wehner et al., 1977b; Phillips et al., 1978). No translocation of talc into the
ovaries was detected after single or multiple intravaginal applications of talc to rabbits
(Phillips et al., 1978) or monkeys (Wehner et al., 1985, 1986).

4.2.2    Toxic effects
    Reviews of the literature on the biological effects of talc in experimental animals are
available (Lord, 1978; Wehner, 1994).
    [The Working Group noted that in most of the studies of ‘talc’ described below, no or
limited characterization of the mineralogy of the sample employed was given, and, in
particular, information on fibre content or particle size was lacking.]

         (a)    Chronic toxicity
    Mild to marked arterial endothelial cell proliferation with cellular encroachment into
the lumen, the occurrence of occasional foreign-body giant cells within the endothelial
masses and moderate thickening of the intra-alveolar septa of the lungs were observed
                                           TALC                                           397

after intravenous injections of talc in rabbits and guinea-pigs (Puro et al., 1966; Dogra
et al., 1977). No effect on the rat lung was observed after intravenous injection of talc
(Schepers & Durkan, 1955b) but talc granulomas were seen in rats following intrasplenic
injection of talc (Eger & Canaliss, 1964).
     No chronic pathological effect was associated with oral administration of Italian talc
(92% pure; 100 mg per day on 101 days over 5 months) to rats (Wagner et al., 1977).
Intratracheal injections of talc (total dose, 150 mg) into guinea-pigs induced perivascular
and peribronchiolar focal accumulations of histiocytes, fibrocytes, plasma cells and
eosinophils within 1 month. After 2 years, the dominant effects were bronchiolectasia,
bronchiolitis and marked fibrosis (Schepers & Durkan 1955b).
     Rats exposed to dust clouds of 30–383 mg/m3 ‘industrial’- or ‘pharmaceutical’-grade
talc for 9 months developed chronic inflammatory changes including thickening of the
walls of the pulmonary arteries and, eventually, emphysema (Bethge-Iwańska, 1971).
     In rats exposed by inhalation to 10.8 mg/m3 Italian talc (grade 00000; ready milled;
mean particle size, 25 μm) for 3 months, minimal fibrosis was observed, the degree of
which did not change during the observation period after exposure. Animals that were
exposed for 1 year had minimal to slight fibrosis, the degree of which had increased to
moderate within 1 year after cessation of exposure (Wagner et al., 1977). In contrast,
Syrian golden hamsters exposed to 8-mg/m3 aerosols of cosmetic-grade talc for up to
150 minutes per day on 5 days a week for 30 days showed no histopathological change in
the lungs, heart, liver, renal tissues, stomach or uterus (Wehner et al., 1977c).
     Two years after injection of 20 mg Italian talc (see above) into the right pleural cavity
of rats, granulomas at the injection site were common, and one small pulmonary adenoma
was observed, but no other relevant pathology was seen in the lungs (Wagner et al.,
1977).
     Groups of male and female rats, 6–7 weeks old, were exposed to aerosols of 0, 6 or
18 mg/m3 talc until mortality in any exposure group reached 80% (113 weeks for males
and 122 weeks for females). These exposure concentrations provided a dose equivalent of
0, 2.8 or 8.4 mg/kg bw per day for male rats and 0, 3.2 or 9.6 mg/kg bw per day for
female rats. The talc used for this study was MP 10–52 Grade (see Section 3.2.1) and was
found to be free from asbestos by polarized light microscopy and transmission electron
microscopy. Survival of male and female rats was similar to that of the controls. Mean
body weights of rats exposed to 18 mg/m3 were slightly lower than those of controls after
week 65. No clinical findings were attributed to exposure to talc. Absolute and relative
lung weights of male rats exposed to 18 mg/m3 were significantly greater than those of
controls at the 6-, 11- and 18-month interim evaluations and at the end of the lifetime
study, while those of female rats exposed to 18 mg/m3 were significantly greater at the
11-, 18- and 24-month interim evaluations and at the end of the study. Talc produced a
spectrum of inflammatory, reparative and proliferative processes in the lungs. The
principal toxic lesions observed included chronic granulomatous inflammation, alveolar
epithelial hyperplasia, squamous metaplasia, squamous cysts and interstitial fibrosis of the
lung. These lesions were accompanied by impaired pulmonary function characterized
398                        IARC MONOGRAPHS VOLUME 93

primarily by reduced lung volumes, reduced dynamic and/or quasistatic lung compliance,
reduced gas-exchange efficiency and non-uniform intrapulmonary gas distribution
(National Toxicology Program, 1993).
     Groups of male and female B6C3F1 mice, 7 weeks of age, were exposed by
inhalation to aerosols that contained 0, 6 or 18 mg/m3 MP 10–52 grade talc (see Section
3.2.1) for up to 104 weeks (dose equivalents, 0, 2 or 6 mg/kg bw per day for male mice
and 0, 1.3 or 3.9 mg/kg bw per day for female mice). Survival and final mean body
weights of male and female mice exposed to talc were similar to those of the controls. No
clinical findings were attributed to exposure to talc. Inhalation exposure to talc was
associated with chronic inflammation and accumulation of macrophages in the lung.
Accumulations of macrophages (histiocytes) containing talc particles were also observed
in the bronchial lymph nodes (National Toxicology Program, 1993).

         (b)    In-vitro toxicity
     A concentration >50 μg/mL Italian talc caused a 50% reduction in the colony-forming
efficiency of cultured Chinese hamster V79-4 lung cells (Chamberlain & Brown, 1978).
     The concentration of talc (99% pure) required to cause 50% haemolysis of red blood
cells was 6.5 mg/mL, which is more than 50-fold that of chrysotile. A concentration of
0.1 mg/mL talc caused 35% release of 51Cr from Syrian hamster tracheal epithelial cells
labelled with radioactive sodium chromate; the concentration was twofold that required
for chrysotile (Woodworth et al., 1982).
     Davies et al. (1983) examined the effect of different types of talc on mouse peritoneal
macrophages in vitro. Macrophages were exposed to seven specimens of high-purity talcs
and the release of lactate dehydrogenase and β-glucuronidase was measured. These
enzymes are produced by macrophages after they digest materials that can induce fibrosis
and chronic inflammation. Enzyme release after exposure of macrophages to quartz, a
known fibrogenic dust, and magnetite, a non-fibrogenic dust, was also measured. Quartz
caused the greatest cytotoxic reaction in vitro: the amount of enzyme released increased
with the dose. Magnetite had no effect. All seven talc specimens were cytotoxic to the
macrophages: the levels of enzymes released were dose-related but were lower than those
observed after exposure to quartz. The results show that talc is cytotoxic to macrophages
and may be able to induce fibrosis and chronic inflammation in animals. However, the
macrophage response to talc appears to be weaker than that for other fibrogenic dusts
such as quartz, and the response of macrophages to talc may be different in vivo.
     Talc caused the release of several cytokines including C-X-C and C-C chemokines
from normal human pleural mesothelial cells (Nasreen et al., 1998). Pleural mesothelial
cells exposed to talc did not undergo apoptosis, whereas malignant mesothelioma cell
lines (ATTC CRL-2081, CRL-5820, CRL-5915) exposed to the same dose did (Nasreen
et al., 2000). Talc also caused the release of basic fibroblast growth factor in pleural
mesothelial cells (Antony et al., 2004).
     In bone marrow-derived macrophages from mice, talc was found to stimulate DNA
synthesis ([3H]thymidine incorporation) (Hamilton et al., 2001).
                                             TALC                                             399

4.2.3     Genetic and related effects
    Three samples of respirable talc failed to elicit significant unscheduled DNA
synthesis (10, 20 and 50 µg/cm2, 24 hours), sister chromatid exchange or aneuploidy (2,
5, 10 and 15 µg/cm2, 48 hours) in rat pleural mesothelial cells, in contrast to various
positive controls. The three samples, i.e Spanish talc (No. 5725), Italian talc (No. 5726)
and French talc (No. 7841), contained 90–95% talc; the remaining contents were chlorite
and dolomite. Electron microscopy analysis revealed that talc particles were taken up by
the rat pleural mesothelial cells, but no aneuploidy was observed in metaphases (Endo-
Capron et al., 1993).

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                         5. Summary of Data Reported

5.1      Exposure data

     The term ‘talc’ refers to both mineral talc and industrial mineral products that contain
mineral talc in proportions that range from about 35% to almost 100% and are marketed
under the name talc. Mineral talc occurs naturally in many regions of the world where
metamorphosed mafic and ultramafic rocks or magnesium carbonates occur. Mineral talc
is usually platy but may also occur as asbestiform fibres. (Asbestiform refers to a habit
(pattern) of mineral growth and not to the presence of other minerals. Asbestiform talc
must not be confused with talc that contains asbestos.) Together with platy talc,
asbestiform talc is found in the Gouverneur District of New York State, USA, and
occasionally elsewhere; it may be associated with other minerals as observed by
transmission electron microscopy.
     Talc products vary in their particle size, associated minerals and talc content
depending on their source and application. Minerals commonly found in talc products
include chlorite and carbonate. Less commonly, talc products contain tremolite,
anthophyllite and serpentine.
     Mineral talc is valued for its softness, platyness, inertness and ability to absorb
organic matter. It is used in agricultural products, ceramics, paint and other coatings,
paper, plastics, roofing, rubber, cosmetics and pharmaceuticals and for waste treatment.
Cosmetic talc, which contains more than 90% mineral talc, is present in many cosmetic
products and is used for many purposes, including baby powders and feminine hygiene
products. The type of talc that is currently used for cosmetic purposes in the USA does
not contain detectable levels of amphibole, including asbestos. It is not known whether
this is true in other countries.
     Workers are exposed to talc during its mining and milling. Reported geometric mean
exposure levels to respirable dust are typically in the range of 1–5 mg/m3. Workers may
also be exposed in user industries, primarily in the rubber, pulp and paper and ceramics
industries. Due to the presence of other particulates, exposure levels may be difficult to
measure accurately. Consumer exposure by inhalation could occur during the use of loose
powders that contain talc.
     Accurate estimates of prevalence are not available. However, in some series of
controls from epidemiological studies of ovarian cancer, the prevalence of use for
feminine hygiene of body powders, baby powders, talcum powders and deodorizing
powders, most of which contain cosmetic talc in varying amounts, has been reported to be
as high as 50% in some countries. Perineal use for such purposes seems to have been a
common practice in Australia, Canada, the United Kingdom, the USA and other
countries, including Pakistan. Use of cosmetic talc in the USA has declined steadily since
the late 1970s.
                                          TALC                                          407

5.2      Human carcinogenicity data

    The carcinogenic effect of exposure to talc not contaminated by asbestos fibres has
been investigated in five independent but relatively small cohort studies of talc miners and
millers in Austria, France, Italy, Norway and the USA. The miners and to a lesser extent
the millers in these cohorts were also exposed to quartz. In a case–control study nested in
the combined cohorts of talc workers from Austria and France, there was no tendency of
higher risks for lung cancer by increasing cumulative exposure of workers to talc dust. In
four of five studies, it was explicitly stated that no case of mesothelioma was observed. In
the two studies from Italy and Norway, which included an estimate of cumulative
exposure of the cohort to talc dust, the risk for lung cancer in the highest category was
found to be close to or below unity. In the subgroup of miners in the study in the USA, an
excess risk for lung cancer was found, which may be have been due to exposure in the
workplace to radon daughters and quartz. In all the other groups of workers studied, there
was no increased risk for lung cancer.
    Female workers in the Norwegian pulp and paper industry had an increased risk for
ovarian cancer, which, however, was attributed to exposure to asbestos. A community-
based case–control study did not find an increased risk for ovarian cancer associated with
occupational exposure to talc, but the prevalence of exposure was low.
    Body powder containing talc has been used by women on the perineum (or genital
area), on sanitary napkins and on diaphragms. In total, data from one prospective cohort
study and 19 case–control studies were reviewed in the evaluation of the association of
cosmetic talc use and the risk for ovarian cancer. The information collected on perineal
talc use varied substantially by study (e.g. ever use versus regular use, and whether
information on the mode of application, frequency or duration of use was available).
    The cohort study was conducted among nurses in the USA and included 307 cases of
ovarian cancer that occurred over 900 000 person–years of observation and a maximum
of 14 years of follow-up. Information was collected on the frequency but not duration of
regular use. Perineal use of talc was not associated with a risk for ovarian cancer.
    The 20 case–control studies were conducted in Australia, Canada, China, Greece,
Israel, Norway, the United Kingdom and the USA (nested case–control study), and
included between 77 and 824 cases and 46 and 1367 controls. Five were hospital-based
designs and the others were population-based studies. The Working Group designated a
subset of these studies as being more informative based on the following characteristics:
the study was population-based, was of a reasonable size, had acceptable participation
rates and included information to allow control for potentially important confounders.
    Eight population-based case–control studies from Australia, Canada (Ontario) and the
USA (two non-overlapping studies in Boston, MA, and one each in California, Delaware
Valley, eastern Massachusetts and New Hampshire and Washington State) were thereby
identified as being more informative. The selected studies included at least 188 cases and
had participation rates that generally ranged from 60 to 75%. Among these eight studies,
the prevalence of use of body powder among controls ranged from 16 to 52%; however,
408                        IARC MONOGRAPHS VOLUME 93

information on exposure was not collected in a comparable manner across studies. In
addition, the frequency and duration of use or total lifetime applications were investigated
in several studies as well as consideration of prior tubal ligation or simple hysterectomy.
Only sparse data were available on whether women had used body powder before or after
the mid-1970s.
     The relative risks for ovarian cancer among users of body powder (versus non-users)
were homogenous across this relatively diverse set of eight studies, each of which
indicated a 30–60% increase in risk. Among the other 11 case–control studies, most also
reported relative risks of this magnitude or higher. The subset of studies that assessed use
of talc on a diaphragm were relatively uninformative due to their lack of precision.
     Results on exposure–response relationships were presented in the cohort study and in
seven of the more informative case–control studies. In the cohort study, no exposure–
response trend was apparent. Positive exposure–response trends were apparent in the two
Boston-based studies that presented the most comprehensive analysis. In the Canadian
and Californian studies, a non-significant, weakly positive trend was observed for either
duration or frequency of use, but not for both. In the other three case–control studies, no
consistent trend was observed and the strongest associations tended to be seen among the
shorter-term or less frequent talc users.
     The cohort study and four of the eight more informative case–control studies
presented results on histological type of ovarian cancer. When the analysis of the cohort
study was restricted to the 160 serous invasive cases, a statistically significant increase in
risk of about 40% was observed. The risk increased with increasing frequency of body
powder use. Risks for serous ovarian cancer were somewhat greater than those for other
histological types in two of the four case–control studies in which the contrast was
reported. Results for other histological types were inconclusive.
     The Working Group carefully weighed the various limitations and biases that could
have influenced these findings. Non-differential misclassification of talc use, given the
relatively crude definitions available, would have attenuated any true association.
Although the available information on potential confounders varied by study, most
investigators accounted for age, oral contraceptive use and parity. In most studies, only
the adjusted relative risks were presented; however, in the three studies in which both age-
adjusted and fully adjusted estimates were provided, relative risks did not differ
materially, suggesting minimal residual confounding.
     It is possible that confounding by unrecognized risk factors may have distorted the
results. One or more such factors, if they are causes of ovarian cancer and also associated
in the population with perineal use of talc, could induce the appearance of an association
between the use of talc and ovarian cancer where there is none. In order for such an
unrecognized risk factor to induce the consistent pattern of excess risks in all of the case–
control studies, it would be necessary for the factor to be associated with perineal talc use
across different countries and different decades. While the range of countries and decades
covered by the more informative case–control studies is not very broad, it provides some
                                            TALC                                           409

diversity of social and cultural context and thereby reduces the likelihood of a hidden
confounder.
     There was a distinct pattern of excess risk discernible in all of the case–control studies
when users were compared with non-users; however, methodological factors needed to be
considered. First, while chance cannot be ruled out as an explanation, it seemed very
unlikely to be responsible for the consistent pattern of excess risks. A second possible
explanation would be recall bias, to which case–control studies may be particularly
susceptible. This may have been the case if there had been widespread publicity about the
possible association between the use of body powder and cancer. In such circumstances, it
is possible that women who had ovarian cancer could be more likely than women who did
not to remember or over-report a habit, such as body powder use, if they thought that it
may have played a role in their illness..There was a flurry of publicity in the USA in the
mid-1970s concerning the possible risks for cancer posed by the use of talc-based body
powders. Following an industry decision to market talc powders with no asbestos, it was
the opinion of the Working Group that there had not been widespread public concern
about this issue, at least until very recently. Therefore, the Working Group considered it
unlikely that such a bias could explain the set of consistent findings that stretch over two
decades. The Working Group believed that recall bias was a possibility inherent in the
case–control studies and could not be ruled out. The Working Group also considered
publication and selection biases and these were not judged to have substantially
influenced the pattern of findings.
     The Working Group searched for documentation on the presence of known hazardous
minerals in talc-based body powders. There were strong indications that these products
contained quartz in the mid-1970s and still do. There were also indications that occasional
small concentrations of asbestos were present in these products before the mid-1970s, but
the available information was sparse, sampling methods and detection limits were not
described, and the range of locations where data were available was extremely limited. As
a result, the Working Group found it difficult to identify a date before which talc-based
body powders contained other hazardous minerals and after which they did not, or to have
confidence that this would be applicable worldwide. In addition, the epidemiological
studies generally do not provide information about the years during which the female
subjects were exposed. Consequently, the Working Group could not identify studies in
which an uncontaminated form of talc was the only one used by study subjects.
Nevertheless, the Working Group noted that, even in the most recent studies in the USA,
where exposure histories may have been much less affected by hazardous contaminants of
talc, the risk estimates were not different from the early studies in which the possibility of
such exposure was more likely.
     To evaluate the evidence on whether perineal use of talc causes an increased risk for
ovarian cancer, the Working Group noted the following:
     • The eight more informative case–control studies, as well as most of the less
     informative ones, provided overall estimates of excess risk that were remarkably
     consistent; seven of these eight case–control studies examined exposure–response
410                         IARC MONOGRAPHS VOLUME 93

      relationships; two provided evidence supporting such a relationship, two provided
      mixed evidence and three did not support an association.
      • The cohort study neither supports nor strongly refutes the evidence from the case–
      control studies.
      • Case–control studies were susceptible to recall bias which could tend to inflate risk
      estimates but to an unknown degree.
      • All of the studies were susceptible to other potential biases which could either
      increase or decrease the association.
      • All of the studies involved some degree of non-differential misclassification of
      exposure that would tend to underestimate any true underlying association.

5.3        Animal carcinogenicity data

     Talc of different grades was tested for carcinogenicity in mice by inhalation exposure,
intrathoracic, intraperitoneal and subcutaneous injection, in rats by inhalation exposure,
intrathoracic injection, intraperitoneal injection, oral administration and intrapleural and
ovarian implantation, and in hamsters by inhalation exposure and intratracheal injection.
     In male and female rats exposed by inhalation to a well-defined talc, the incidence of
alveolar/bronchiolar carcinoma or adenoma and carcinoma (combined) was significantly
increased in female rats. The incidence of adrenal medulla pheochromocytomas (benign,
malignant or complex (combined)) showed a significant positive trend and the incidence
in high-dose males and females was significantly greater than that in controls. The
incidence of malignant pheochromocytomas was also increased in high-dose females. The
Working Group did not consider it probable that the increased incidence of
pheochromocytomas was causally related to talc but, based on the experimental data
available, neither could talc-related effects be excluded.
     Tumour incidence was not increased following the intrapleural or intrathoracic
administration of a single dose of various talcs to rats. In two studies of intraperitoneal
administration in rats, no increase in the incidence of mesotheliomas was observed. No
increased incidence of tumours was produced in rats in two studies of talc administered in
the diet or in another study of the implantation of talc on to the ovary.
     Tumour incidence was not increased in mice following the inhalation of talc in one
study, the intrathoracic administration of a single dose of various talcs in another study or
the administration of talc by intraperitoneal injections in three studies. A single
subcutaneous injection of talc into mice did not produce local tumours.
     Tumour incidence was not increased following inhalation or intratracheal
administration of talc to hamsters.

5.4        Mechanistic considerations and other relevant data

    Different mechanisms are probably operative in the effects of talc on the lung and
pleura, depending on the route of exposure.
                                           TALC                                          411

    In humans, deposition, retention and clearance of talc have been insufficiently
studied, although talc particles have been found at autopsy in the lungs of talc workers.
    In humans and experimental animals, the effects of talc are dependent on the route of
exposure, and the dose and properties of the talc. Talc pneumoconiosis was somewhat
more prevalent and severe among miners exposed to talc containing asbestiform minerals
and/or asbestos than among those exposed to talc without such contaminants. However,
the role of quartz and asbestos in the observed pneumoconiosis could not be ruled out.
Among drug users, intravenous injection of talc present as a filler in the drugs resulted in
microembolization in a variety of organs and alterations in pulmonary function.
    In animal studies, talc has been shown to cause granulomas and mild inflammation
when inhaled. Observations of the effects that occurred in the lungs of rats exposed by
inhalation to talc suggested that the operative mechanisms may be similar to those
identified for carbon black, and talc is known to cause the release of cytokines,
chemokines and growth factors from pleural mesothelial cells.
    In humans, intrapleural administration of talc as a therapeutic procedure results in
pleural inflammation which leads to pleural fibrosis and symphysis. Pleural fibrosis is the
intended effect of intrapleural administration of talc in patients with malignant pleural
effusions or pneumothorax. Animal studies suggested that extrapulmonary transport of
talc following pleurodesis increases with decreasing particle size and increasing
administered dose. Talc has been shown to cause apoptosis of malignant cells in vitro.
    Perineal exposure to cosmetic talc in women is of concern because of its possible
association with ovarian cancer. Several studies have been conducted in women to assess
potential retrograde movement of particles through the reproductive tract to the ovaries.
These have been conducted in women who were about to undergo gynaecological
surgery, most of whom had diseases or complications of the reproductive tract and organs
that required surgery. The findings reported in these studies may be confounded by the
various levels of dysfunction in clearance from the female reproductive tract due to
underlying pathologies. In addition, most of the studies had little or no further information
on the use of talc products for perineal hygiene or changes in habits that may have
preceded surgery. On balance, the Working Group believed that the evidence for
retrograde transport of talc to the ovaries in normal women is weak. In women with
impaired clearance function, some evidence of retrograde transport was found. Studies in
animals (rodents, langomorphs and non-human primates) showed no evidence of
retrograde transport of talc to the ovaries.
    In one study, predictors of the presence of antibodies to mucin protein were inversely
related to the risk for ovarian cancer and exposure to powder containing talc.
    No data were available on the genotoxic effects of exposure to talc in humans. The
limited number of studies available on the genetic toxicology of talc in vitro gave
negative results.
412                        IARC MONOGRAPHS VOLUME 93

                           6. Evaluation and Rationale

6.1      Cancer in humans

    There is inadequate evidence in humans for the carcinogenicity of inhaled talc not
containing asbestos or asbestiform fibres.
    There is limited evidence in humans for the carcinogenicity of perineal use of talc-
based body powder.

6.2      Cancer in experimental animals

    There is limited evidence in experimental animals for the carcinogenicity of talc not
containing asbestos or asbestiform fibres.

6.3      Overall evaluation

    Perineal use of talc-based body powder is possibly carcinogenic to humans (Group
2B).
    Inhaled talc not containing asbestos or asbestiform fibres is not classifiable as to its
carcinogenicity (Group 3).

6.4      Rationale
    In making this evaluation the Working Group considered the human and animal
evidence as well as evidence regarding the potential mechanisms through which talc
might cause cancer in humans.
    The Working Group found little or inconsistent evidence of an increased risk for
cancer in the studies of workers occupationally exposed to talc. The studies of talc miners
and millers were considered to provide the best source of evidence, but no consistent
pattern was seen. One study observed an excess risk for lung cancer among miners, but
confounding from exposure to other carcinogens made it difficult to attribute this to talc
and no excess risk was seen in millers. Other studies also found no increased cancer risk
or no higher risk with increasing cumulative exposure. Overall, these results led the
Working Group to conclude that there was inadequate evidence from epidemiological
studies to assess whether inhaled talc not containing asbestos or asbestiform fibres causes
cancer in humans.
    For perineal use of talc-based body powder, many case–control studies of ovarian
cancer found a modest, but unusually consistent, excess in risk, although the impact of
bias and potential confounding could not be ruled out. In addition, the evidence regarding
exposure–response was inconsistent and the one cohort study did not provide support for
an association between talc use and ovarian cancer. Concern was also expressed that
                                          TALC                                         413

exposure was defined in a variety of ways and that some substances called talc may have
contained quartz and other potentially carcinogenic materials. A small number of
Working Group members considered the evidence to be inadequate. Despite these
reservations, the Working Group concluded that the epidemiological studies taken
together provide limited evidence of an association between perineal use of talc-based
body powder and an increased risk for ovarian cancer.
    In one study of rats that inhaled talc, an excess incidence of malignant lung tumours
was seen in females. The same study observed an excess incidence of
pheochromocytomas in the adrenal medulla in both sexes, but the Working Group was
divided as to whether these rare tumours could be attributed to exposure to talc. Other
studies in rats and mice using different routes of administration did not find an excess of
cancer, and two studies in rats were considered to be inadequate for evaluation. Based on
the one positive study, the Working Group found that there was limited evidence of
carcinogenicity of inhaled talc in experimental animals. There was no agreement within
the Working Group as to whether the evidence on pheochromocytomas should be taken
into account in the evaluation of animal data.

				
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